The seminal properties and female fertility factors were studied in 45 couples where homologous in- seminations were performed. For 10 couples (group I) normal coitus was impossible. In this group there were 8 normal pregnancies and 1 miscarriage. For 35 couples (group 11) the postcoital test showed persistently reduced penetration because of poor semen quality or hostility of the cervical mucus. In this group there were 10 concep tions, 4 normal pregnancies and 6 miscarriages. The semen quality was a more important prognostic than pathological findings in the women. In vitro sperm penetration of cervical mucus seemed to be the best criterion for judging the prognosis. Homologous insemination can be of value in the treatment of infertility, but careful selection of patients is needed.