We have developed analytical expressions for the crosscorrelation between users at unequal bit rates (chip rates are equal), i.e. for multi-rate (multi-processing gain) CDMA. These expressions for the crosscorrelations were used to generate data for Gold & Kasami sequences. The results of our calculations show that Gold and Kasami sequences' crosscorrelation performance in a multi-rate scheme is very close to the performance calculated when assuming random sequences.