A method and system is disclosed for coordinating codec consistency based on cross-carrier assignments. When a new voice call (or other communication session) is set up between access terminals in a wireless communication system, a network device, such a base station, can determine a respective maximum coding rate supported on carrier frequencies of both an originating access terminal and a terminating access terminal. The network device can then select a coding rate that best accommodates the respective maximum coding rates. Each access terminal may then be instructed to use the selected coding rate for the new call (or communication session). Either or both access terminals may also execute a frequency handoff to a carrier frequency that supports the selected coding rate, if necessary.