A mechanism to enable multiple message threads management in the context of the Converged IP Messaging (CPM) service and in the context of CPM inter-working with SMS is provided. A CPM user can simply start a message-based conversation with another CPM or Short Message Service (SMS) user without explicitly establishing a session beforehand. All messages that belong to a given conversation are displayed in the corresponding conversational view (i.e. window) in the CPM user device, even if the conversation is stopped and restarted at a later time, and even if there are multiple message threads available (currently active or stored) in the CPM device. Message structures and behavior of the CPM system elements to enable the functionalities above as well as a mechanism makes the message threads management possible even between a CPM user and an SMS user are also provided.