Linear dispersion codes (LDC) designed for multiple input multiple output (MIMO) wireless systems are examples of space-time codes which try to maximize the mutual information between the transmitter and receiver. However, such codes are typically designed for flat fading channels. It is possible to extend LDC designs for frequency selective fading channels using Orthogonal Frequency Division Multiplexing (OFDM). Additionally, the multipath diversity available as frequency diversity could be potentially exploited by properly designed space-frequency LDC codes for MIMO-OFDM systems. In this paper, the design criteria to obtain such space-frequency LDC along with the error-rate performance of such codes in frequency selective fading channels are provided. © 2005 IEEE.