— In this paper, we design and investigate a novel Interleave Division Multiplexing based Space-Time Code (IDM-STC) in the context of cooperative communications. We outline the particular signalling scheme used for exchanging the necessary information amongst the cooperating MSs and suggest an efficient interleaver allocation scheme, which is capable of uniquely and unambiguously differentiating the different MSs’ signals with the aid of their user and antenna-specific interleavers. We then characterize the achievable performance of our proposed IDM-STC design and compare it to that of the traditional G2 and G4 Space-Time Block Code (STBC) invoked for cooperative communications. Our cooperative IDM-STC scheme is flexible in terms of forming a cluster of cooperative users, it is power-efficient and capable of maintaining a high rate, in particular when combined with non-uniform power allocation.