We are concerned with the performance evaluation of code allocation algorithms in Universal Mobile Telecommunication System (UMTS) networks. UMTS networks will offer multiple services (voice, data, video, etc.) with different quality-of-service (QoS) requirements to mobile users. We evaluate the performance of different code (rate) allocation algorithms on the UMTS uplink in a mixed voice/data traffic scenario. Two different code allocation algorithms are considered, one based on the overall buffer occupancy at the user terminal, and the other based on dividing the available codes equally among the requesting users. Further, for a data-only system, we evaluate the performance of two algorithms for rate and power allocation based on received signal-to-interference ratio (SIR) at the base station.