diff --git a/libethereum/Client.cpp b/libethereum/Client.cpp
index 630a845ad..8a35f4e9c 100644
--- a/libethereum/Client.cpp
+++ b/libethereum/Client.cpp
@@ -156,7 +156,7 @@ void Client::transact(Secret _secret, u256 _value, Address _dest, bytes const& _
 	m_changed = true;
 }
 
-void Client::transact(Secret _secret, u256 _endowment, bytes const& _code, bytes const& _init, u256 _gas, u256 _gasPrice)
+Address Client::transact(Secret _secret, u256 _endowment, bytes const& _code, bytes const& _init, u256 _gas, u256 _gasPrice)
 {
 	lock_guard<recursive_mutex> l(m_lock);
 	Transaction t;
@@ -171,6 +171,7 @@ void Client::transact(Secret _secret, u256 _endowment, bytes const& _code, bytes
 	cnote << "New transaction " << t;
 	m_tq.attemptImport(t.rlp());
 	m_changed = true;
+	return right160(sha3(rlpList(t.sender(), t.nonce)));
 }
 
 void Client::work()
diff --git a/libethereum/Client.h b/libethereum/Client.h
index d2a670df5..c7a87cf96 100644
--- a/libethereum/Client.h
+++ b/libethereum/Client.h
@@ -87,7 +87,8 @@ public:
 	void transact(Secret _secret, u256 _value, Address _dest, bytes const& _data = bytes(), u256 _gas = 10000, u256 _gasPrice = 10 * szabo);
 
 	/// Submits a new contract-creation transaction.
-	void transact(Secret _secret, u256 _endowment, bytes const& _code, bytes const& _init = bytes(), u256 _gas = 10000, u256 _gasPrice = 10 * szabo);
+	/// @returns the new contract's address (assuming it all goes through).
+	Address transact(Secret _secret, u256 _endowment, bytes const& _code, bytes const& _init = bytes(), u256 _gas = 10000, u256 _gasPrice = 10 * szabo);
 
 	/// Makes the given call. Nothing is recorded into the state. TODO
 //	bytes call(Secret _secret, u256 _amount, u256 _gasPrice, Address _dest, u256 _gas, bytes _data = bytes());