A method and apparatus for supporting machine-type communications (MTC) are disclosed. A wireless transmit/receive unit (WTRU) may configure itself to operate in a mobile-originated-only mode. The WTRU may perform no, or a subset of, radio resource control (RRC) idle and/or non-access stratum (NAS) idle/standby state procedures in the mobile-originated-only mode. For example, the WTRU may perform cell reselection but not paging monitoring in the mobile-originated-only mode. Alternatively, the WTRU may perform paging monitoring but not cell reselection and location update. The operation in the mobile-originated-only mode may be triggered explicitly or implicitly. For example, the WTRU may operate in the mobile-originated-only mode if an inactivity timer expires. The WTRU may switch the mode in accordance with a pre-configured schedule. After transition of the operation mode, the WTRU may send a message to the network indicating such mode switch.