Wideband Code Division Multiple Access (WCDMA) is one of the air interface techniques proposed for the third generation (3G) mobile communication system. WCDMA was selected because it fulfills the IMT-2000 requirements for higher data rate trans mission, support of multimedia capabilities and other flexible services due to its variable bit rates and larger bandwidth, improved capacity and coverage, efficient power control and support for advanced and improved detector structures. Performance evaluation of 3G wireless network through simulation plays an important role in the design and implementation of the actual system, aiding the wireless system designer by providing them the necessary performance conformance statistics prior to implementation. In accordance with this goal, a simulator engine was developed entirely on a MATLAB platform to emulate the behaviour of the WCDMA air interface for both the uplink and downlink in a real world fading mobile environment. This paper discuss the development of the simulator along with a brief description of its functionalities and user interface. The WCDMA air interface mode focused in this paper is in accordance to the 3GPPs frequency division duplex (FDD) mode and restricted to the physical layer description. Performance results for the selected cases for the downlink, uplink, varying mobile velocity and sampling rates are also provided.