Systems and methods are disclosed to provide converged service control and converged charging in legacy networks and IMS networks. A converged service control system of the invention includes a protocol interface and a service controller. The protocol interface receives call messages from the legacy networks and the IMS networks, and converts the call messages to a common protocol. The service controller then processes the call messages in the common protocol to provide service control to the legacy networks and the IMS networks. The service controller is also enabled to provide online and offline charging for the legacy networks and the IMS networks.