A system and method of providing a Push To All (PTA) service enables a PTA service terminal having limited resources to efficiently perform a multi session, while performing a PTA service such as Push To Talk (PTT), Push To Video (PTV) or Message Session Relay Protocol (MSRP) with a second PTA terminal via an already established session, by rejecting another session requested by a third terminal upon a service type of the session being the same as a service type of the already established session, and by accepting the session upon the service type of the session being different from the already established session.