A method and apparatus for admission control and resource tracking in a wireless communication system are disclosed. A wireless transmit/receive unit (WTRU) and a base station maintain parameters for admission control including parameters for the amount of time available for admission of traffic of each access category and for the amount of time available for admission of all access categories and parameters for admitted time and used time for the WTRU. Upon receipt of an admission request for a traffic stream from the WTRU, the base station determines whether to accept or deny the request based on the medium time for the requested traffic stream and the available time for the access category and total available time. The base station tracks the actually transmitted time by the WTRU, reclaims the unused time and returns the reclaimed time to either a common pool or to the WTRU as needed.