An OFDM system with CPM mappers is considered. Such a system in general is known to enhance bit error rate performance by virtue of the memory introduced by the CPM mapper compared to OFDM systems with conventional memoryless mappers such as BPSK and QPSK. In this paper, the ability of CPM mappers in an OFDM system to reduce Peak-to-Average Power Ratio (PAPR) is examined as a function of modulation parameters of mappers used in the system. Various subclasses of CPM mapper such as single-h CPFSK, multi-h CPFSK, and asymmetric multi-h CPFSK are also considered. Next, these mappers in conjunction with Clipping and Filtering (CF) technique are considered and it is shown that repeated clipping and frequency domain filtering in OFDM systems can significantly reduce the PAPR of the transmitted signal. The technique causes no increase in out-of-band power and significant PAPR reduction can be achieved with only moderate levels of clipping. A comparison of PAPR reduction capability of CPM mappers relative to memoryless BPSK mappers in an OFDM system is presented. It is noted that, in general, CPM mappers offer superior PAPR performance compared to memoryless mappers in an OFDM system.