Closed-form expressions for computing the average bit error rate (BER) for a class of modulation schemes in Ricean flat fading channels with maximal-ratio combining diversity and channel estimation errors are derived. The results are valid for a general multichannel model that includes Ricean and Rayleigh fading channels. The results are applicable to channel estimators that are jointly Gaussian with the channel gain. The BER performance of pilot symbol-assisted modulation is studied. The effects of estimation error on the diversity system are examined as well as the influences of varying the Ricean factor K and changing the number of diversity branches L.