The timing and frequency of AID were reviewed in 36 women who received menotropin therapy. One hundred thirteen treatment cycles were reviewed with AID done once per cycle in 39, twice per cycle in 63, and three times per cycle in 11 cases. The pregnancy rate was 19.5% per treatment cycle, with 21 of the 36 patients (58%) conceiving. No difference in pregnancy rate was found with single or multiple inseminations when AID application included the day of hCG administration. Evidence is presented that suggests that frequently the fertilizing sperm may have resided in the woman for over 30 hours before fertilization occurred.