Recently, we proposed a joint iterative transmit/receive (Tx/Rx) minimum mean square error (MMSE) frequency-domain equalization (FDE) & inter-symbol interference (ISI) cancellation (ISIC) for single-carrier (SC) block transmissions. In this paper, we extend the previously proposed joint iterative Tx/Rx MMSE-FDE & ISIC to the SC hybrid automatic repeat request (HARQ) packet access to exploit the retransmission of the same packet for improving the throughput. We optimize the set of Tx/Rx MMSE-FDE weights by taking into account the packet retransmission/combining as well as ISIC. We show by computer simulation that the proposed scheme significantly improves the packet error rate (PER) and throughput performances in a severe frequency-selective fading channel.