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The effects of cross-correlation interference and intensity fading on the error rate performance of an optical code division multiple-access communication system are investigated. The system model is a multiaccess satellite repeater in which user separation is accomplished by direct sequence modulation. The analysis is for direct detection, optical polarization modulation systems. Generalized expressions for the conditional probability of error for the uplink and downlink channels are derived in terms of the number of active users, signal strength and the normalized cross-correlation between user codes. Numerical results are obtained for systems of two users, for both length 31 and 127 Gold codes. Analysis of a random sampling of the length 31 codes has shown that performance is significantly dependent on the magnitude of the normalized second moment of the cross-correlation between user codes. Further analysis showed that the error probability decreases with increasing code length. The multiuser capabilities of the uplink and downlink channels were shown to differ significantly.