To improve the frequency efficiency and the transmission performance of differential chaos shift keying under wireless fading channel, a multi-carrier chaotic shift keying communication scheme is proposed. In each block size of M OFDM symbols, one pilot OFDM symbol inserted time-spaced in all-frequency is used to transmit the reference chaotic signal and the other M-1 OFDM symbols is used to transmit the informationbearing signals, which spread by the reference chaotic signal. At the receiver, a differential detector is constructed and the information bits from the correlations between the pilot OFDM symbol and the other M-1 OFDM symbols in each block size of M are recovered. A multi-carrier chaotic shift keying transceiver under MIMO multipath fading channels with no channel state information is presented, in which a distinct chaotic sequence at each transmit antenna is used to spread the same data symbol and the detection statistics at each receive antenna are combined with equal gain for symbol detection. Both performance analysis and computer simulations show that multi-carrier chaotic shift keying outperforms differential chaos shift keying in additive white Gaussian noise channels with high bandwidth efficiency for the block size of M>2 and that multicarrier chaotic shift keying achieves both spatial diversity gain and frequent diversity gain under MIMO multipath fading channels.