diff --git a/rpc/types.go b/rpc/types.go
index 806c9c8a4..bc9a46ed5 100644
--- a/rpc/types.go
+++ b/rpc/types.go
@@ -43,16 +43,11 @@ func (d *hexdata) MarshalJSON() ([]byte, error) {
 	return json.Marshal(d.String())
 }
 
-func (d *hexdata) UnmarshalJSON(b []byte) (err error) {
-	d.data = common.FromHex(string(b))
-	return nil
-}
-
 func newHexData(input interface{}) *hexdata {
 	d := new(hexdata)
 
 	if input == nil {
-		d.data = nil
+		d.isNil = true
 		return d
 	}
 	switch input := input.(type) {
@@ -105,19 +100,19 @@ func newHexData(input interface{}) *hexdata {
 	case int16:
 		d.data = big.NewInt(int64(input)).Bytes()
 	case uint16:
-		buff := make([]byte, 8)
+		buff := make([]byte, 2)
 		binary.BigEndian.PutUint16(buff, input)
 		d.data = buff
 	case int32:
 		d.data = big.NewInt(int64(input)).Bytes()
 	case uint32:
-		buff := make([]byte, 8)
+		buff := make([]byte, 4)
 		binary.BigEndian.PutUint32(buff, input)
 		d.data = buff
 	case string: // hexstring
 		d.data = common.Big(input).Bytes()
 	default:
-		d.data = nil
+		d.isNil = true
 	}
 
 	return d
@@ -147,11 +142,6 @@ func (d *hexnum) MarshalJSON() ([]byte, error) {
 	return json.Marshal(d.String())
 }
 
-func (d *hexnum) UnmarshalJSON(b []byte) (err error) {
-	d.data = common.FromHex(string(b))
-	return nil
-}
-
 func newHexNum(input interface{}) *hexnum {
 	d := new(hexnum)
 
diff --git a/rpc/types_test.go b/rpc/types_test.go
index 91f0152dc..9ef7b8d38 100644
--- a/rpc/types_test.go
+++ b/rpc/types_test.go
@@ -1,7 +1,13 @@
 package rpc
 
 import (
+	"bytes"
+	"encoding/json"
+	"math/big"
 	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
 )
 
 func TestInvalidTypeError(t *testing.T) {
@@ -48,3 +54,151 @@ func TestValidationError(t *testing.T) {
 		t.Error(err.Error())
 	}
 }
+
+func TestHexdataMarshalNil(t *testing.T) {
+	hd := newHexData([]byte{})
+	hd.isNil = true
+	v, _ := json.Marshal(hd)
+	if string(v) != "null" {
+		t.Errorf("Expected null, got %s", v)
+	}
+}
+
+func TestHexnumMarshalNil(t *testing.T) {
+	hn := newHexNum([]byte{})
+	hn.isNil = true
+	v, _ := json.Marshal(hn)
+	if string(v) != "null" {
+		t.Errorf("Expected null, got %s", v)
+	}
+}
+
+func TestHexdataNil(t *testing.T) {
+	v := newHexData(nil)
+	if v.isNil != true {
+		t.Errorf("Expected isNil to be true, but is %v", v.isNil)
+	}
+}
+
+func TestHexdataPtrHash(t *testing.T) {
+	in := common.Hash{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31}
+	v := newHexData(&in)
+	if bytes.Compare(in.Bytes(), v.data) != 0 {
+		t.Errorf("Got % x expected % x", in, v.data)
+	}
+}
+
+func TestHexdataPtrHashNil(t *testing.T) {
+	var in *common.Hash
+	in = nil
+	v := newHexData(in)
+	if !v.isNil {
+		t.Errorf("Expect isNil to be true, but is %v", v.isNil)
+	}
+}
+
+func TestHexdataPtrAddress(t *testing.T) {
+	in := common.Address{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19}
+	v := newHexData(&in)
+	if bytes.Compare(in.Bytes(), v.data) != 0 {
+		t.Errorf("Got % x expected % x", in, v.data)
+	}
+}
+
+func TestHexdataPtrAddressNil(t *testing.T) {
+	var in *common.Address
+	in = nil
+	v := newHexData(in)
+	if !v.isNil {
+		t.Errorf("Expect isNil to be true, but is %v", v.isNil)
+	}
+}
+
+func TestHexdataPtrBloom(t *testing.T) {
+	in := types.Bloom{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19}
+	v := newHexData(&in)
+	if bytes.Compare(in.Bytes(), v.data) != 0 {
+		t.Errorf("Got % x expected % x", in, v.data)
+	}
+}
+
+func TestHexdataPtrBloomNil(t *testing.T) {
+	var in *types.Bloom
+	in = nil
+	v := newHexData(in)
+	if !v.isNil {
+		t.Errorf("Expect isNil to be true, but is %v", v.isNil)
+	}
+}
+
+func TestHexdataBigintNil(t *testing.T) {
+	var in *big.Int
+	in = nil
+	v := newHexData(in)
+	if !v.isNil {
+		t.Errorf("Expect isNil to be true, but is %v", v.isNil)
+	}
+}
+
+func TestHexdataUint(t *testing.T) {
+	var in = uint(16)
+	var expected = []byte{0x10}
+	v := newHexData(in)
+	if bytes.Compare(expected, v.data) != 0 {
+		t.Errorf("Expected % x got % x", expected, v.data)
+	}
+}
+
+func TestHexdataInt8(t *testing.T) {
+	var in = int8(16)
+	var expected = []byte{0x10}
+	v := newHexData(in)
+	if bytes.Compare(expected, v.data) != 0 {
+		t.Errorf("Expected % x got % x", expected, v.data)
+	}
+}
+
+func TestHexdataUint8(t *testing.T) {
+	var in = uint8(16)
+	var expected = []byte{0x10}
+	v := newHexData(in)
+	if bytes.Compare(expected, v.data) != 0 {
+		t.Errorf("Expected % x got % x", expected, v.data)
+	}
+}
+
+func TestHexdataInt16(t *testing.T) {
+	var in = int16(16)
+	var expected = []byte{0x10}
+	v := newHexData(in)
+	if bytes.Compare(expected, v.data) != 0 {
+		t.Errorf("Expected % x got % x", expected, v.data)
+	}
+}
+
+func TestHexdataUint16(t *testing.T) {
+	var in = uint16(16)
+	var expected = []byte{0x0, 0x10}
+	v := newHexData(in)
+	if bytes.Compare(expected, v.data) != 0 {
+		t.Errorf("Expected % x got % x", expected, v.data)
+	}
+}
+
+func TestHexdataInt32(t *testing.T) {
+	var in = int32(16)
+	var expected = []byte{0x10}
+	v := newHexData(in)
+	if bytes.Compare(expected, v.data) != 0 {
+		t.Errorf("Expected % x got % x", expected, v.data)
+	}
+}
+
+func TestHexdataUint32(t *testing.T) {
+	var in = uint32(16)
+	var expected = []byte{0x0, 0x0, 0x0, 0x10}
+	v := newHexData(in)
+	if bytes.Compare(expected, v.data) != 0 {
+		t.Errorf("Expected % x got % x", expected, v.data)
+	}
+}