A method and apparatus for transmitting and receiving between MSs and a BS orthogonal code index information indicating orthogonal codes available to the MSs in a mobile communication system supporting multimedia services including voice and data services. The MSs are connected to the BS and receive a data service simultaneously from the BS. The BS generates the orthogonal code index information according to the forward channel states of the MSs, and transmits it to the MSs. Each of the MSs determines its assigned orthogonal codes from received orthogonal code index information.