Abstract The behavior of four-wave mixing (FWM) in 2-D time-spreading wavelength-hopping (TW) optical code-division multiple-access (OCDMA) systems with coherent light sources is introduced. The analysis is performed in terms of several key system parameters, in particular, transmitted power per chip, wavelength spacing, number of active users, code weight,fiber type, and transmission length. To accomplish such study, the number of generated FWM components should be calculated first. Thus, for the first time, a general form for the FWM power generated in 2-D TW OCDMA systems is presented and explicit formulas for the number of FWM products that fall on each signal chip for symmetric codes are given.