Many murine monoclonal antibodies against MUC1 mucin have been analysed for reactivity against short overlapping peptides with sequences based upon that of the 20 amino acid tandem repeat of the MUC1 protein core, in order to identify the minimum binding units or epitopes. This report summarises the findings using a set of overlapping heptamers to identify the epitopes of 5 established anti-MUC1 antibodies. The results are evaluated and reviewed in comparison to those obtained using other length peptides and other assay formats for epitope mapping using the Pepscan technique.