Based on the reported sex difference in the incidence of acquired cystic kidney disease (ACKD) in patients with chronic renal failure, it is hypothesized that the hormonal derangement, well documented in male and female uremic patients on long-term dialysis, could be responsible for the pathogenesis of ACKD. The decreased androgen/estrogen ratio, and the increased estrogen value could be responsible for an estrogen receptor mediated effect on the tubular epithelial cell proliferation, an event further potentiated by the action of regulatory peptides like epidermal growth factor (EGF). The epithelial stimulation is more pronounced in men because male tissues are less adapted than female tissues to high estrogen values. Furthermore the androgen reduction, more remarkable in male than female patients, is responsible for an up-regulation of EGF-R. Therefore hormones and growth factors, by means of their own receptor in renal tissue (homologous to the two oncogenes c-erb A and c-erb B), may be responsible for the development of ACKD, and may play an important role in the pathogenesis of multiple adenomas and renal carcinomas reported with high incidence among uremic patients with ACKD.