An apparatus and method for maintaining an Internet Protocol (IP) connection in a portable terminal is provided. The method includes when there is a request for registration of a service or an application having a push function, determining whether a first service quality interval corresponding to the service or application, registration of which has been requested, has been stored in the memory, and periodically transmitting a keep-alive message for maintaining the IP connection by using the first service quality interval when the first service quality interval has been stored in the memory.