Factors influencing the probability of conception after artificial insemination with donor semen were investigated in a series of 80 infertile couples. Overall, 46 pregnancies were achieved for a crude pregnancy rate of 58%. Life table analysis showed a cumulative probability of conception of 97.1% at the end of 12 cycles and an average fecundability of 15.1%. These results were achieved using a single insemination per cycle and individualizing the day of insemination based on the woman's basal body temperature. Women who had been pregnant previously had a significantly better fecundability than nulligravid women (P less than .05). The overall rates of conception in those women who required therapy for ovulatory dysfunction were the same as normal women although the fecundability was somewhat lower. Women who had abdominal pathology had an overall conception rate of 23%.