diff --git a/MemTrie.cpp b/MemTrie.cpp
index 5c819ffbd..b5d875acb 100644
--- a/MemTrie.cpp
+++ b/MemTrie.cpp
@@ -25,9 +25,10 @@
 #include <libethcore/SHA3.h>
 #include <libethcore/CommonEth.h>
 using namespace std;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
-namespace eth
+namespace dev
 {
 
 #define ENABLE_DEBUG_PRINT 0
@@ -54,7 +55,7 @@ public:
 #endif
 
 	/// 256-bit hash of the node - this is a SHA-3/256 hash of the RLP of the node.
-	h256 hash256() const { RLPStream s; makeRLP(s); return eth::sha3(s.out()); }
+	h256 hash256() const { RLPStream s; makeRLP(s); return dev::eth::sha3(s.out()); }
 	bytes rlp() const { RLPStream s; makeRLP(s); return s.out(); }
 	void mark() { m_hash256 = h256(); }
 
@@ -199,7 +200,7 @@ void MemTrieNode::putRLP(RLPStream& _parentStream) const
 	if (s.out().size() < 32)
 		_parentStream.APPEND_CHILD(s.out());
 	else
-		_parentStream << eth::sha3(s.out());
+		_parentStream << dev::eth::sha3(s.out());
 }
 
 void TrieBranchNode::makeRLP(RLPStream& _intoStream) const
@@ -228,7 +229,7 @@ void TrieInfixNode::makeRLP(RLPStream& _intoStream) const
 
 MemTrieNode* MemTrieNode::newBranch(bytesConstRef _k1, std::string const& _v1, bytesConstRef _k2, std::string const& _v2)
 {
-	uint prefix = commonPrefix(_k1, _k2);
+	unsigned prefix = commonPrefix(_k1, _k2);
 
 	MemTrieNode* ret;
 	if (_k1.size() == prefix)
@@ -347,7 +348,7 @@ MemTrieNode* TrieInfixNode::insert(bytesConstRef _key, std::string const& _value
 	}
 	else
 	{
-		uint prefix = commonPrefix(_key, m_ext);
+		unsigned prefix = commonPrefix(_key, m_ext);
 		if (prefix)
 		{
 			// one infix becomes two infixes, then insert into the second
@@ -478,3 +479,4 @@ void MemTrie::remove(std::string const& _key)
 }
 
 }
+
diff --git a/MemTrie.h b/MemTrie.h
index 8c90f2f3f..66669653c 100644
--- a/MemTrie.h
+++ b/MemTrie.h
@@ -24,7 +24,7 @@
 #include <libethential/Common.h>
 #include <libethential/FixedHash.h>
 
-namespace eth
+namespace dev
 {
 
 class MemTrieNode;
diff --git a/TestHelper.cpp b/TestHelper.cpp
index 06f188a89..02a883dbc 100644
--- a/TestHelper.cpp
+++ b/TestHelper.cpp
@@ -19,11 +19,14 @@
  * @date 2014
  */
 
+#include "TestHelper.h"
+
 #include <thread>
 #include <chrono>
 #include <libethereum/Client.h>
-#include "TestHelper.h"
 
+namespace dev
+{
 namespace eth
 {
 
@@ -47,3 +50,4 @@ void connectClients(Client& c1, Client& c2)
 }
 
 }
+}
diff --git a/TestHelper.h b/TestHelper.h
index 748373baa..d6924a17c 100644
--- a/TestHelper.h
+++ b/TestHelper.h
@@ -21,10 +21,15 @@
 
 #pragma once
 
+namespace dev
+{
 namespace eth
 {
 
+class Client;
+
 void mine(Client& c, int numBlocks);
 void connectClients(Client& c1, Client& c2);
 
 }
+}
diff --git a/TrieHash.cpp b/TrieHash.cpp
index 8f4161a17..b2ebce731 100644
--- a/TrieHash.cpp
+++ b/TrieHash.cpp
@@ -25,9 +25,10 @@
 #include <libethcore/SHA3.h>
 #include <libethcore/CommonEth.h>
 using namespace std;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
-namespace eth
+namespace dev
 {
 
 /*/
@@ -67,12 +68,12 @@ void hash256rlp(HexMap const& _s, HexMap::const_iterator _begin, HexMap::const_i
 	{
 		// find the number of common prefix nibbles shared
 		// i.e. the minimum number of nibbles shared at the beginning between the first hex string and each successive.
-		uint sharedPre = (uint)-1;
-		uint c = 0;
+		unsigned sharedPre = (unsigned)-1;
+		unsigned c = 0;
 		for (auto i = std::next(_begin); i != _end && sharedPre; ++i, ++c)
 		{
-			uint x = std::min(sharedPre, std::min((uint)_begin->first.size(), (uint)i->first.size()));
-			uint shared = _preLen;
+			unsigned x = std::min(sharedPre, std::min((unsigned)_begin->first.size(), (unsigned)i->first.size()));
+			unsigned shared = _preLen;
 			for (; shared < x && _begin->first[shared] == i->first[shared]; ++shared) {}
 			sharedPre = std::min(shared, sharedPre);
 		}
diff --git a/TrieHash.h b/TrieHash.h
index 391c42633..4d86c4dbf 100644
--- a/TrieHash.h
+++ b/TrieHash.h
@@ -24,7 +24,7 @@
 #include <libethential/Common.h>
 #include <libethential/FixedHash.h>
 
-namespace eth
+namespace dev
 {
 
 bytes rlp256(StringMap const& _s);
diff --git a/crypto.cpp b/crypto.cpp
index c39de78d7..2e4ffa055 100644
--- a/crypto.cpp
+++ b/crypto.cpp
@@ -29,7 +29,8 @@
 #include <boost/test/unit_test.hpp>
 
 using namespace std;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
 
 BOOST_AUTO_TEST_CASE(crypto_tests)
@@ -145,7 +146,7 @@ int cryptoTest()
 		int ret = secp256k1_ecdsa_recover_compact((byte const*)hmsg.data(), (int)hmsg.size(), (byte const*)sig64.data(), pubkey.data(), &pubkeylen, 0, (int)t.vrs.v - 27);
 		pubkey.resize(pubkeylen);
 		cout << "RECPUB: " << dec << ret << " " << pubkeylen << " " << toHex(pubkey) << endl;
-		cout << "SENDER: " << hex << toAddress(eth::sha3(bytesConstRef(&pubkey).cropped(1))) << dec << endl;
+		cout << "SENDER: " << hex << toAddress(dev::eth::sha3(bytesConstRef(&pubkey).cropped(1))) << dec << endl;
 	}
 #endif
 	return 0;
diff --git a/dagger.cpp b/dagger.cpp
index 4f65b47aa..fd60a8efa 100644
--- a/dagger.cpp
+++ b/dagger.cpp
@@ -25,7 +25,8 @@
 #include <libethcore/Dagger.h>
 using namespace std;
 using namespace std::chrono;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
 int daggerTest()
 {
diff --git a/fork.cpp b/fork.cpp
index f0edb702f..1cdb8822c 100644
--- a/fork.cpp
+++ b/fork.cpp
@@ -27,7 +27,8 @@
 #include <libethereum/EthereumHost.h>
 #include "TestHelper.h"
 using namespace std;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
 // Disabled since tests shouldn't block. Need a short cut to avoid real mining.
 /*
diff --git a/genesis.cpp b/genesis.cpp
index 441826e78..be6655aba 100644
--- a/genesis.cpp
+++ b/genesis.cpp
@@ -28,7 +28,8 @@
 #include <boost/test/unit_test.hpp>
 
 using namespace std;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
 namespace js = json_spirit;
 
diff --git a/hexPrefix.cpp b/hexPrefix.cpp
index 5ea670923..7dbe80a57 100644
--- a/hexPrefix.cpp
+++ b/hexPrefix.cpp
@@ -27,7 +27,8 @@
 #include <boost/test/unit_test.hpp>
 
 using namespace std;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 namespace js = json_spirit;
 
 BOOST_AUTO_TEST_CASE(hexPrefix_test)
diff --git a/main.cpp b/main.cpp
index 1497f2981..08142095c 100644
--- a/main.cpp
+++ b/main.cpp
@@ -38,7 +38,8 @@ int peerTest(int argc, char** argv);
 #include <libethential/Log.h>
 #include <libethcore/BlockInfo.h>
 using namespace std;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
 BOOST_AUTO_TEST_CASE(basic_tests)
 {
diff --git a/network.cpp b/network.cpp
index 978d68934..acdd649d9 100644
--- a/network.cpp
+++ b/network.cpp
@@ -27,7 +27,8 @@
 #include <libethereum/EthereumHost.h>
 #include "TestHelper.h"
 using namespace std;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
 // Disabled since tests shouldn't block (not the worst offender, but timeout should be reduced anyway).
 /*
diff --git a/peer.cpp b/peer.cpp
index f903d0429..821aab514 100644
--- a/peer.cpp
+++ b/peer.cpp
@@ -24,8 +24,8 @@
 #include <thread>
 #include <libp2p/Host.h>
 using namespace std;
-using namespace eth;
-using namespace p2p;
+using namespace dev;
+using namespace dev::p2p;
 
 int peerTest(int argc, char** argv)
 {
diff --git a/rlp.cpp b/rlp.cpp
index 548be8d9b..963d61091 100644
--- a/rlp.cpp
+++ b/rlp.cpp
@@ -30,10 +30,10 @@
 #include <algorithm>
 
 using namespace std;
-using namespace eth;
+using namespace dev;
 namespace js = json_spirit;
 
-namespace eth 
+namespace dev
 {
 	namespace test
 	{
@@ -116,7 +116,7 @@ namespace eth
 				BOOST_CHECK( !u.isData() ); 
 				js::mArray& arr = v.get_array(); 
 				BOOST_CHECK( u.itemCount() == arr.size() ); 
-				uint i; 
+				unsigned i; 
 				for( i = 0; i < arr.size(); i++ ) 
 				{ 
 					RLP item = u[i]; 
@@ -137,16 +137,16 @@ BOOST_AUTO_TEST_CASE(rlp_encoding_test)
 {
 	cnote << "Testing RLP Encoding...";
 	js::mValue v;
-	eth::test::getRLPTestCases(v); 
+	dev::test::getRLPTestCases(v);
 
 	for (auto& i: v.get_obj())
 	{
 		js::mObject& o = i.second.get_obj();
 		cnote << i.first;
-		eth::test::checkRLPTestCase(o); 
+		dev::test::checkRLPTestCase(o);
 
 		RLPStream s;
-		eth::test::buildRLP(o["in"], s);
+		dev::test::buildRLP(o["in"], s);
 
 		std::string expectedText(o["out"].get_str()); 
 		std::transform(expectedText.begin(), expectedText.end(), expectedText.begin(), ::tolower ); 
@@ -173,19 +173,19 @@ BOOST_AUTO_TEST_CASE(rlp_decoding_test)
 	// and then compare the output structure to the json of the 
 	// input object. 
 	js::mValue v;
-	eth::test::getRLPTestCases(v); 
+	dev::test::getRLPTestCases(v);
 	for (auto& i: v.get_obj())
 	{
 		js::mObject& o = i.second.get_obj();
 		cnote << i.first;
-		eth::test::checkRLPTestCase(o); 
+		dev::test::checkRLPTestCase(o);
 		
 		js::mValue& inputData = o["in"];
 		bytes payloadToDecode = fromHex(o["out"].get_str()); 
 
 		RLP payload(payloadToDecode); 
 
-		eth::test::checkRLPAgainstJson(inputData, payload); 
+		dev::test::checkRLPAgainstJson(inputData, payload);
 
 	}
 }
diff --git a/state.cpp b/state.cpp
index 8d82b0c2b..99ce30957 100644
--- a/state.cpp
+++ b/state.cpp
@@ -26,7 +26,8 @@
 #include <libethereum/State.h>
 #include <libethereum/Defaults.h>
 using namespace std;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
 int stateTest()
 {
diff --git a/trie.cpp b/trie.cpp
index b28be8b18..4ddf30a61 100644
--- a/trie.cpp
+++ b/trie.cpp
@@ -29,22 +29,23 @@
 #include <boost/test/unit_test.hpp>
 
 using namespace std;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
 namespace js = json_spirit;
 
-namespace eth 
-{ 
-	namespace test
-	{
-		static unsigned fac(unsigned _i) 
-		{ 
-			return _i > 2 ? _i * fac(_i - 1) : _i; 
-		}
+namespace dev
+{
+namespace test
+{
 
-	}
+static unsigned fac(unsigned _i)
+{
+	return _i > 2 ? _i * fac(_i - 1) : _i;
 }
 
+}
+}
 
 BOOST_AUTO_TEST_CASE(trie_tests)
 {
@@ -66,7 +67,7 @@ BOOST_AUTO_TEST_CASE(trie_tests)
 			if (!ss.back().second.find("0x"))
 				ss.back().second = asString(fromHex(ss.back().second.substr(2)));
 		}
-		for (unsigned j = 0; j < min(1000u, eth::test::fac((unsigned)ss.size())); ++j)
+		for (unsigned j = 0; j < min(1000u, dev::test::fac((unsigned)ss.size())); ++j)
 		{
 			next_permutation(ss.begin(), ss.end());
 			MemoryDB m;
diff --git a/txTest.cpp b/txTest.cpp
index 314cf9644..cc78c26a2 100644
--- a/txTest.cpp
+++ b/txTest.cpp
@@ -27,7 +27,8 @@
 #include <libethereum/EthereumHost.h>
 #include "TestHelper.h"
 using namespace std;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
 // Disabled since tests shouldn't block. Need a short cut to avoid real mining.
 /*
@@ -46,7 +47,7 @@ BOOST_AUTO_TEST_CASE(mine_local_simple_tx)
 	//send c2 some eth from c1
 	auto txAmount = c1bal / 2u;
 	auto gasPrice = 10 * szabo;
-	auto gas = eth::c_callGas;
+	auto gas = dev::eth::c_callGas;
 	c1.transact(kp1.secret(), txAmount, kp2.address(), bytes(), gas, gasPrice);
 
 	//mine some more to include the transaction on chain
@@ -74,7 +75,7 @@ BOOST_AUTO_TEST_CASE(mine_and_send_to_peer)
 	//send c2 some eth from c1
 	auto txAmount = c1bal / 2u;
 	auto gasPrice = 10 * szabo;
-	auto gas = eth::c_callGas;
+	auto gas = dev::eth::c_callGas;
 	c1.transact(kp1.secret(), txAmount, kp2.address(), bytes(), gas, gasPrice);
 
 	//mine some more to include the transaction on chain
@@ -105,7 +106,7 @@ BOOST_AUTO_TEST_CASE(mine_and_send_to_peer_fee_check)
 	//send c2 some eth from c1
 	auto txAmount = c1StartBalance / 2u;
 	auto gasPrice = 10 * szabo;
-	auto gas = eth::c_callGas;
+	auto gas = dev::eth::c_callGas;
 	c1.transact(kp1.secret(), txAmount, c2.address(), bytes(), gas, gasPrice);
 
 	//mine some more, this time with second client (so he can get fees from first client's tx)
diff --git a/vm.cpp b/vm.cpp
index 0647849a0..2b75f0b3d 100644
--- a/vm.cpp
+++ b/vm.cpp
@@ -33,9 +33,10 @@
 
 using namespace std;
 using namespace json_spirit;
-using namespace eth;
+using namespace dev;
+using namespace dev::eth;
 
-namespace eth { namespace test {
+namespace dev { namespace test {
 
 class FakeExtVM: public ExtVMFace
 {
@@ -387,7 +388,7 @@ void doTests(json_spirit::mValue& v, bool _fillin)
 		BOOST_REQUIRE(o.count("exec") > 0);
 
 		VM vm;
-		eth::test::FakeExtVM fev;
+		dev::test::FakeExtVM fev;
 		fev.importEnv(o["env"].get_obj());
 		fev.importState(o["pre"].get_obj());
 
@@ -419,7 +420,7 @@ void doTests(json_spirit::mValue& v, bool _fillin)
 			BOOST_REQUIRE(o.count("out") > 0);
 			BOOST_REQUIRE(o.count("gas") > 0);
 
-			eth::test::FakeExtVM test;
+			dev::test::FakeExtVM test;
 			test.importState(o["post"].get_obj());
 			test.importCallCreates(o["callcreates"].get_array());
 			int i = 0;
@@ -481,7 +482,7 @@ BOOST_AUTO_TEST_CASE(vm_tests)
 		string s = asString(contents("../../../cpp-ethereum/test/vmtests.json"));
 		BOOST_REQUIRE_MESSAGE(s.length() > 0, "Contents of 'vmtests.json' is empty.");
 		json_spirit::read_string(s, v);
-		eth::test::doTests(v, true);
+		dev::test::doTests(v, true);
 		writeFile("../../../tests/vmtests.json", asBytes(json_spirit::write_string(v, true)));
 	}
 /*	catch (std::exception const& e)
@@ -496,7 +497,7 @@ BOOST_AUTO_TEST_CASE(vm_tests)
 		string s = asString(contents("../../../tests/vmtests.json"));
 		BOOST_REQUIRE_MESSAGE(s.length() > 0, "Contents of 'vmtests.json' is empty. Have you cloned the 'tests' repo branch develop?");
 		json_spirit::read_string(s, v);
-		eth::test::doTests(v, false);
+		dev::test::doTests(v, false);
 	}
 	catch (std::exception const& e)
 	{