In this paper, we investigate the performance of a coded cooperation diversity using relay nodes in the decode-and-forward (DF) mode, in which the codewords of the source node are partitioned and transmitted through independent fading channels to both the relay and destination nodes. The application of such a cooperative coding scheme is shown to offer remarkable gains over a noncooperative system. Unlike noncooperative space-time coding, in distributed cooperative coding, the link between the source and the relay node is not error-free. In this work, we take into account the errors in the source-relay link and derive the outage probability of DF relaying for binary phase shift keying (BPSK) transmission. Our analytical results show that the proposed scheme achieves full diversity. This is different from conventional relay systems where the relay nodes operating in the DF mode are based on symbol-by-symbol decoding and forwarding. Numerical results are shown to support our analytical expression.