In this paper, the performance of a multicarrier frequency-hopping/binary frequencyshift keying (MC-FH/BFSK) system with jamming is evaluated. The communication channel is assumed to be Rayleigh fading channel. The considered types of jamming are partial band and broadband jamming. A closed-form expression of the average probability of error due to jamming is obtained. It is found that a smart jammer should be present in all subbands of the MC-FH/BFSK system in order to be effective. Also, a performance comparison between MC-FH/BFSK and single carrier FH/BFSK systems is presented. It is found that, the performance of MC-FH/BFSK under jamming is better than the performance of FH/BFSK.