diff --git a/core/state/state_object.go b/core/state/state_object.go
index 0379af2de2..81ff205b86 100644
--- a/core/state/state_object.go
+++ b/core/state/state_object.go
@@ -96,8 +96,7 @@ type Account struct {
 	Root     common.Hash // merkle root of the storage trie
 	CodeHash []byte
 
-	// TODO(fjl): track code size here to get it into the cache
-	// codeSize int
+	codeSize *int
 }
 
 // NewObject creates a state object.
@@ -269,9 +268,20 @@ func (self *StateObject) Code(db trie.Database) []byte {
 	return code
 }
 
+// CodeSize returns the size of the contract code associated with this object.
+func (self *StateObject) CodeSize(db trie.Database) int {
+	if self.data.codeSize == nil {
+		self.data.codeSize = new(int)
+		*self.data.codeSize = len(self.Code(db))
+	}
+	return *self.data.codeSize
+}
+
 func (self *StateObject) SetCode(code []byte) {
 	self.code = code
 	self.data.CodeHash = crypto.Keccak256(code)
+	self.data.codeSize = new(int)
+	*self.data.codeSize = len(code)
 	self.dirty, self.dirtyCode = true, true
 }
 
diff --git a/core/state/statedb.go b/core/state/statedb.go
index 097e5a1a6f..2dd833f584 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -171,6 +171,14 @@ func (self *StateDB) GetCode(addr common.Address) []byte {
 	return nil
 }
 
+func (self *StateDB) GetCodeSize(addr common.Address) int {
+	stateObject := self.GetStateObject(addr)
+	if stateObject != nil {
+		return stateObject.CodeSize(self.db)
+	}
+	return 0
+}
+
 func (self *StateDB) GetState(a common.Address, b common.Hash) common.Hash {
 	stateObject := self.GetStateObject(a)
 	if stateObject != nil {
diff --git a/core/vm/environment.go b/core/vm/environment.go
index 747627565e..4bd03de7eb 100644
--- a/core/vm/environment.go
+++ b/core/vm/environment.go
@@ -94,6 +94,7 @@ type Database interface {
 	GetNonce(common.Address) uint64
 	SetNonce(common.Address, uint64)
 
+	GetCodeSize(common.Address) int
 	GetCode(common.Address) []byte
 	SetCode(common.Address, []byte)
 
diff --git a/core/vm/instructions.go b/core/vm/instructions.go
index a95ba26c52..849a8463cc 100644
--- a/core/vm/instructions.go
+++ b/core/vm/instructions.go
@@ -363,7 +363,7 @@ func opCalldataCopy(instr instruction, pc *uint64, env Environment, contract *Co
 
 func opExtCodeSize(instr instruction, pc *uint64, env Environment, contract *Contract, memory *Memory, stack *Stack) {
 	addr := common.BigToAddress(stack.pop())
-	l := big.NewInt(int64(len(env.Db().GetCode(addr))))
+	l := big.NewInt(int64(env.Db().GetCodeSize(addr)))
 	stack.push(l)
 }