diff --git a/beacon_node/beacon_chain/src/beacon_chain.rs b/beacon_node/beacon_chain/src/beacon_chain.rs
index 9ad4d5414..67e4646c6 100644
--- a/beacon_node/beacon_chain/src/beacon_chain.rs
+++ b/beacon_node/beacon_chain/src/beacon_chain.rs
@@ -148,11 +148,12 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         );
 
         // Slot clock
-        let slot_clock = T::SlotClock::new(
+        let slot_clock = T::SlotClock::from_eth2_genesis(
             spec.genesis_slot,
             genesis_state.genesis_time,
-            spec.seconds_per_slot,
-        );
+            Duration::from_secs(spec.seconds_per_slot),
+        )
+        .ok_or_else(|| Error::SlotClockDidNotStart)?;
 
         Ok(Self {
             spec,
@@ -224,18 +225,13 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         Ok(())
     }
 
-    /// Reads the slot clock, returns `Err` if the slot is unavailable.
+    /// Returns the slot _right now_ according to `self.slot_clock`. Returns `Err` if the slot is
+    /// unavailable.
     ///
     /// The slot might be unavailable due to an error with the system clock, or if the present time
     /// is before genesis (i.e., a negative slot).
-    ///
-    /// This is distinct to `present_slot`, which simply reads the latest state. If a
-    /// call to `read_slot_clock` results in a higher slot than a call to `present_slot`,
-    /// `self.state` should undergo per slot processing.
-    pub fn present_slot(&self) -> Result<Slot, Error> {
-        self.slot_clock
-            .present_slot()
-            .ok_or_else(|| Error::UnableToReadSlot)
+    pub fn slot(&self) -> Result<Slot, Error> {
+        self.slot_clock.now().ok_or_else(|| Error::UnableToReadSlot)
     }
 
     /// Returns the beacon block body for each beacon block root in `roots`.
@@ -348,10 +344,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
     pub fn catchup_state(&self) -> Result<(), Error> {
         let spec = &self.spec;
 
-        let present_slot = self
-            .slot_clock
-            .present_slot()
-            .ok_or_else(|| Error::UnableToReadSlot)?;
+        let present_slot = self.slot()?;
 
         if self.state.read().slot < present_slot {
             let mut state = self.state.write();
@@ -394,7 +387,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
     /// Reads the slot clock (see `self.read_slot_clock()` and returns the number of slots since
     /// genesis.
     pub fn slots_since_genesis(&self) -> Option<SlotHeight> {
-        let now = self.slot_clock.present_slot()?;
+        let now = self.slot().ok()?;
         let genesis_slot = self.spec.genesis_slot;
 
         if now < genesis_slot {
@@ -847,10 +840,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
             return Ok(BlockProcessingOutcome::GenesisBlock);
         }
 
-        let present_slot = self
-            .slot_clock
-            .present_slot()
-            .ok_or_else(|| Error::UnableToReadSlot)?;
+        let present_slot = self.slot()?;
 
         if block.slot > present_slot {
             return Ok(BlockProcessingOutcome::FutureSlot {
@@ -1013,9 +1003,8 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
     ) -> Result<(BeaconBlock<T::EthSpec>, BeaconState<T::EthSpec>), BlockProductionError> {
         let state = self.state.read().clone();
         let slot = self
-            .slot_clock
-            .present_slot()
-            .ok_or_else(|| BlockProductionError::UnableToReadSlot)?;
+            .slot()
+            .map_err(|_| BlockProductionError::UnableToReadSlot)?;
 
         self.produce_block_on_state(state, slot, randao_reveal)
     }
@@ -1191,7 +1180,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         *self.state.write() = {
             let mut state = self.canonical_head.read().beacon_state.clone();
 
-            let present_slot = self.present_slot()?;
+            let present_slot = self.slot()?;
 
             // If required, transition the new state to the present slot.
             for _ in state.slot.as_u64()..present_slot.as_u64() {
diff --git a/beacon_node/beacon_chain/src/test_utils.rs b/beacon_node/beacon_chain/src/test_utils.rs
index 6ab657b08..c45a22fd8 100644
--- a/beacon_node/beacon_chain/src/test_utils.rs
+++ b/beacon_node/beacon_chain/src/test_utils.rs
@@ -151,7 +151,7 @@ where
             // Determine the slot for the first block (or skipped block).
             let state_slot = match block_strategy {
                 BlockStrategy::OnCanonicalHead => {
-                    self.chain.present_slot().expect("should have a slot") - 1
+                    self.chain.slot().expect("should have a slot") - 1
                 }
                 BlockStrategy::ForkCanonicalChainAt { previous_slot, .. } => previous_slot,
             };
@@ -161,16 +161,14 @@ where
 
         // Determine the first slot where a block should be built.
         let mut slot = match block_strategy {
-            BlockStrategy::OnCanonicalHead => {
-                self.chain.present_slot().expect("should have a slot")
-            }
+            BlockStrategy::OnCanonicalHead => self.chain.slot().expect("should have a slot"),
             BlockStrategy::ForkCanonicalChainAt { first_slot, .. } => first_slot,
         };
 
         let mut head_block_root = None;
 
         for _ in 0..num_blocks {
-            while self.chain.present_slot().expect("should have a slot") < slot {
+            while self.chain.slot().expect("should have a slot") < slot {
                 self.advance_slot();
             }
 
diff --git a/beacon_node/client/src/lib.rs b/beacon_node/client/src/lib.rs
index 2612fd648..004353d38 100644
--- a/beacon_node/client/src/lib.rs
+++ b/beacon_node/client/src/lib.rs
@@ -114,7 +114,7 @@ where
                 .map_err(error::Error::from)?,
         );
 
-        if beacon_chain.read_slot_clock().is_none() {
+        if beacon_chain.slot().is_err() {
             panic!("Cannot start client before genesis!")
         }
 
@@ -124,7 +124,9 @@ where
         // blocks and we're basically useless.
         {
             let state_slot = beacon_chain.head().beacon_state.slot;
-            let wall_clock_slot = beacon_chain.read_slot_clock().unwrap();
+            let wall_clock_slot = beacon_chain
+                .slot()
+                .expect("Cannot start client before genesis");
             let slots_since_genesis = beacon_chain.slots_since_genesis().unwrap();
             info!(
                 log,
@@ -176,7 +178,7 @@ where
         };
 
         let (slot_timer_exit_signal, exit) = exit_future::signal();
-        if let Ok(Some(duration_to_next_slot)) = beacon_chain.slot_clock.duration_to_next_slot() {
+        if let Some(duration_to_next_slot) = beacon_chain.slot_clock.duration_to_next_slot() {
             // set up the validator work interval - start at next slot and proceed every slot
             let interval = {
                 // Set the interval to start at the next slot, and every slot after
@@ -223,7 +225,7 @@ impl<T: BeaconChainTypes> Drop for Client<T> {
 
 fn do_state_catchup<T: BeaconChainTypes>(chain: &Arc<BeaconChain<T>>, log: &slog::Logger) {
     // Only attempt to `catchup_state` if we can read the slot clock.
-    if let Some(current_slot) = chain.read_slot_clock() {
+    if let Ok(current_slot) = chain.slot() {
         let state_catchup_result = chain.catchup_state();
 
         let best_slot = chain.head().beacon_block.slot;
diff --git a/beacon_node/network/src/sync/simple_sync.rs b/beacon_node/network/src/sync/simple_sync.rs
index 49196facc..d3ed2f3e4 100644
--- a/beacon_node/network/src/sync/simple_sync.rs
+++ b/beacon_node/network/src/sync/simple_sync.rs
@@ -387,7 +387,7 @@ impl<T: BeaconChainTypes> SimpleSync<T> {
                 "peer" => format!("{:?}", peer_id),
                 "msg" => "Failed to return all requested hashes",
                 "start_slot" => req.start_slot,
-                "current_slot" => format!("{:?}", self.chain.present_slot()),
+                "current_slot" => format!("{:?}", self.chain.slot()),
                 "requested" => req.count,
                 "returned" => blocks.len(),
             );
diff --git a/beacon_node/rest_api/src/helpers.rs b/beacon_node/rest_api/src/helpers.rs
index 0f47200e9..aeaf5ad6e 100644
--- a/beacon_node/rest_api/src/helpers.rs
+++ b/beacon_node/rest_api/src/helpers.rs
@@ -88,7 +88,7 @@ pub fn state_root_at_slot<T: BeaconChainTypes>(
 ) -> Result<Hash256, ApiError> {
     let head_state = &beacon_chain.head().beacon_state;
     let current_slot = beacon_chain
-        .present_slot()
+        .slot()
         .map_err(|_| ApiError::ServerError("Unable to read slot clock".to_string()))?;
 
     // There are four scenarios when obtaining a state for a given slot:
diff --git a/eth2/types/src/test_utils/builders/testing_beacon_state_builder.rs b/eth2/types/src/test_utils/builders/testing_beacon_state_builder.rs
index 98f840953..4f8a2d924 100644
--- a/eth2/types/src/test_utils/builders/testing_beacon_state_builder.rs
+++ b/eth2/types/src/test_utils/builders/testing_beacon_state_builder.rs
@@ -123,8 +123,10 @@ impl<T: EthSpec> TestingBeaconStateBuilder<T> {
             .collect::<Vec<_>>()
             .into();
 
+        let genesis_time = 1567052589; // 29 August, 2019;
+
         let mut state = BeaconState::new(
-            spec.min_genesis_time,
+            genesis_time,
             Eth1Data {
                 deposit_root: Hash256::zero(),
                 deposit_count: 0,
diff --git a/eth2/utils/slot_clock/src/lib.rs b/eth2/utils/slot_clock/src/lib.rs
index 5986191dc..fd3bf029b 100644
--- a/eth2/utils/slot_clock/src/lib.rs
+++ b/eth2/utils/slot_clock/src/lib.rs
@@ -33,7 +33,7 @@ pub trait SlotClock: Send + Sync + Sized {
 
     fn new(genesis_slot: Slot, genesis: Instant, slot_duration: Duration) -> Self;
 
-    fn present_slot(&self) -> Option<Slot>;
+    fn now(&self) -> Option<Slot>;
 
     fn duration_to_next_slot(&self) -> Option<Duration>;
 
diff --git a/eth2/utils/slot_clock/src/metrics.rs b/eth2/utils/slot_clock/src/metrics.rs
index 1abd93c48..d1de491d0 100644
--- a/eth2/utils/slot_clock/src/metrics.rs
+++ b/eth2/utils/slot_clock/src/metrics.rs
@@ -17,7 +17,7 @@ lazy_static! {
 
 /// Update the global metrics `DEFAULT_REGISTRY` with info from the slot clock.
 pub fn scrape_for_metrics<T: EthSpec, U: SlotClock>(clock: &U) {
-    let present_slot = match clock.present_slot() {
+    let present_slot = match clock.now() {
         Some(slot) => slot,
         _ => Slot::new(0),
     };
diff --git a/eth2/utils/slot_clock/src/system_time_slot_clock.rs b/eth2/utils/slot_clock/src/system_time_slot_clock.rs
index 88c9c0e63..0d4a52ef6 100644
--- a/eth2/utils/slot_clock/src/system_time_slot_clock.rs
+++ b/eth2/utils/slot_clock/src/system_time_slot_clock.rs
@@ -25,7 +25,7 @@ impl SlotClock for SystemTimeSlotClock {
         }
     }
 
-    fn present_slot(&self) -> Option<Slot> {
+    fn now(&self) -> Option<Slot> {
         let now = Instant::now();
 
         if now < self.genesis {
@@ -80,18 +80,18 @@ mod tests {
 
         let clock =
             SystemTimeSlotClock::new(genesis_slot, prior_genesis(0), Duration::from_secs(1));
-        assert_eq!(clock.present_slot(), Some(Slot::new(0)));
+        assert_eq!(clock.now(), Some(Slot::new(0)));
 
         let clock =
             SystemTimeSlotClock::new(genesis_slot, prior_genesis(5), Duration::from_secs(1));
-        assert_eq!(clock.present_slot(), Some(Slot::new(5)));
+        assert_eq!(clock.now(), Some(Slot::new(5)));
 
         let clock = SystemTimeSlotClock::new(
             genesis_slot,
             Instant::now() - Duration::from_millis(500),
             Duration::from_secs(1),
         );
-        assert_eq!(clock.present_slot(), Some(Slot::new(0)));
+        assert_eq!(clock.now(), Some(Slot::new(0)));
         assert!(clock.duration_to_next_slot().unwrap() < Duration::from_millis(500));
 
         let clock = SystemTimeSlotClock::new(
@@ -99,7 +99,7 @@ mod tests {
             Instant::now() - Duration::from_millis(1_500),
             Duration::from_secs(1),
         );
-        assert_eq!(clock.present_slot(), Some(Slot::new(1)));
+        assert_eq!(clock.now(), Some(Slot::new(1)));
         assert!(clock.duration_to_next_slot().unwrap() < Duration::from_millis(500));
     }
 
diff --git a/eth2/utils/slot_clock/src/testing_slot_clock.rs b/eth2/utils/slot_clock/src/testing_slot_clock.rs
index 0b65b1569..d90cb157a 100644
--- a/eth2/utils/slot_clock/src/testing_slot_clock.rs
+++ b/eth2/utils/slot_clock/src/testing_slot_clock.rs
@@ -16,7 +16,7 @@ impl TestingSlotClock {
     }
 
     pub fn advance_slot(&self) {
-        self.set_slot(self.present_slot().unwrap().as_u64() + 1)
+        self.set_slot(self.now().unwrap().as_u64() + 1)
     }
 }
 
@@ -27,7 +27,7 @@ impl SlotClock for TestingSlotClock {
         }
     }
 
-    fn present_slot(&self) -> Option<Slot> {
+    fn now(&self) -> Option<Slot> {
         let slot = *self.slot.read().expect("TestingSlotClock poisoned.");
         Some(slot)
     }
@@ -50,8 +50,8 @@ mod tests {
     #[test]
     fn test_slot_now() {
         let clock = TestingSlotClock::new(Slot::new(10), Instant::now(), Duration::from_secs(0));
-        assert_eq!(clock.present_slot(), Some(Slot::new(10)));
+        assert_eq!(clock.now(), Some(Slot::new(10)));
         clock.set_slot(123);
-        assert_eq!(clock.present_slot(), Some(Slot::new(123)));
+        assert_eq!(clock.now(), Some(Slot::new(123)));
     }
 }
diff --git a/validator_client/src/service.rs b/validator_client/src/service.rs
index 62a782da9..68a913265 100644
--- a/validator_client/src/service.rs
+++ b/validator_client/src/service.rs
@@ -167,11 +167,9 @@ impl<B: BeaconNodeDuties + 'static, S: Signer + 'static, E: EthSpec> Service<B,
             "Unable to start slot clock. Genesis may not have occurred yet. Exiting.".into()
         })?;
 
-        let current_slot = slot_clock
-            .present_slot()
-            .ok_or_else::<error_chain::Error, _>(|| {
-                "Genesis has not yet occurred. Exiting.".into()
-            })?;
+        let current_slot = slot_clock.now().ok_or_else::<error_chain::Error, _>(|| {
+            "Genesis has not yet occurred. Exiting.".into()
+        })?;
 
         /* Generate the duties manager */
 
@@ -293,7 +291,7 @@ impl<B: BeaconNodeDuties + 'static, S: Signer + 'static, E: EthSpec> Service<B,
     fn update_current_slot(&mut self) -> error_chain::Result<()> {
         let current_slot = self
             .slot_clock
-            .present_slot()
+            .now()
             .ok_or_else::<error_chain::Error, _>(|| {
                 "Genesis is not in the past. Exiting.".into()
             })?;