Male breast carcinomas are probably hormone-dependent, but receptor studies are few because this is a relatively rare tumour. We have studied 21 cases of male breast carcinoma immunohistochemically for oestrogen receptor (ER) and epidermal growth factor receptor (EGFR) expression employing the antibodies ER-ICA and 12E on formalin-fixed, paraffin-embedded material. In our series, 86 per cent of male breast cancers were ER-positive and 76 per cent were EGFR-positive. Male breast carcinomas do not exhibit the inverse correlation between ER and EGFR expression that characterizes female breast carcinomas. Owing to the limitations of a small series, we were unable to comment on the relationship between ER and EGFR expression and patient survival. However, the relatively high incidence of ER expression may provide a growth advantage for this tumour in a male environment characterized by low levels of oestrogen. In addition, high EGFR expression may also contribute to a poor prognosis independent of ER status.