The wireless revolution has taken the telecommunication industry by storm. The convenience provided by wireless in the day to day activities is the driving force behind it's popularity. With the increasing demand for such systems, research in multiple access techniques has received much interest. CDMA has been proposed as a next generation multiple access technique for cellular systems. The performance capabilities of a CDMA system are gauged by a variety of methods including analytical studies and simulations. Simulation studies are the most reliable and popular performance measurement techniques. This thesis studies the application of Importance Sampling to the simulation of the IS-95 CDMA standard. Importance Sampling techniques help to achieve the simulation results by sending fewer bits and thus reduce the simulation time by a significant factor. Different versions of Importance Sampling techniques have been discussed and applied to the system. The results of Importance Sampling have been compared with the original results for the Bit Error Rate and Frame Error Rate to prove the validity and the effectiveness of Importance Sampling Techniques. / Master of Science