A retrospective study was designed to examine whether the presence of a hydrosalpinx influenced pregnancy outcome following in-vitro fertilization (IVF) treatment in stimulated cycles. A total of 254 women with tubal lesions were included. Patients with one or two hydrosalpinges were compared with patients having other tubal lesions and pregnancy outcome was analysed. Both pregnancy and delivery rates were significantly higher in the patient group without a hydrosalpinx. The results after frozen embryo transfer showed the same tendency. These findings strongly indicate that a permanent hydrosalpinx has a negative influence on implantation, as well as on pregnancy, and suggest that a more active approach against large hydrosalpinges should be undertaken before IVF treatment, in order to improve the pregnancy rates.