A young female patient with amenorrhea, galactorrhea and hyperprolactinemia developed a carcinoma of the breast a few years later. Examination of the amenorrhea--galactorrhea syndrome did not reveal any prolactinoma so that hyperprolactinemia remains unexplained. Treatment with bromoergocryptine 5 mg daily was successful. The carcinoma was treated in the classic way by amputation of the breast, axillary curettage and adjuvant chemotherapy. However, the association of amenorrhea, galactorrhea and breast carcinoma via hyperprolactinemia raises the question of whether there is any etiologic--pathogenetic relationship. Convincing evidence of such a relationship has not been found in the literature.