Incorporating a framework from multivariate statistical theory, analytical results for the performance of the downlink and uplink of multicarrier code-division multiple access (MC-CDMA) in the presence of correlated Rayleigh fading are presented. Bit-error-probability expressions are derived for MC-CDMA diversity combining schemes, while statistical generality is maintained by assuming no specific form for the covariance matrix of the desired user and interferers. The scenarios of uncorrelated fading among subcarriers and equal-power users are considered as special cases. The analysis is exact in the sense that the error probability is derived without any assumptions on the distribution of the multiple-access interference encountered by a user. With the scenario of independent fading among subcarriers as a baseline, the performance degradation incurred by correlated fading is analyzed for an empirical wireless channel.