A method and apparatus for control of uplink feedback information in contention based wireless communications is disclosed. Uplink feedback information such as a channel quality information and hybrid automatic retransmission request (HARQ) acknowledgement/negative acknowledgement (ACK/NACK) information may be transmitted to the universal terrestrial radio access network (UTRAN) by a wireless transmit/receive unit (WTRU) based on explicit and implicit triggers. Providing more frequent and robust information relating to the channel conditions and HARQ status allows the UTRAN to more efficiently utilize the radio resources for downlink data transmissions.