Summary: This correspondence investigates and compares the capacities of two types of frequency-hopped code-division multiple-access (FH-CDMA) communications systems; namely, multilevel on-off keying (OOK) and MFSK, in particular BFSK. In our multiuser channel model, we assume a random hopping pattern is used for each transmitter-receiver pair, and that the $i$th receiver is only interested in the message transmitted by $i$th transmitter. The degradation in AWGN and nonselective Rayleigh fading environments of both types of FH systems is also investigated and compared.