In this paper, performance of an optical CDMA system with turbo coding is analyzed and simulated. It is assumed that optical channel is an intensity-modulated (IM) channel and direct-detection scheme is employed to detect the received optical signal. The modulation scheme used is pulse-position-modulation (PPM). From the simulation results, it is shown that turbo coding offers considerable coding gain with reasonable encoding/decoding complexity. Also, it is demonstrated that the performance of en optical CDMA system can be substantially improved by increasing the interleaver length and the number of iterations for a fixed code rate. The results in this paper can be applied, for example, to an optical wireless LAN operating in an indoor environment with multiple access applications.