To study the fertility potential of individual semen donors with ejaculates of optimal as compared to suboptimal quality. 363 semen donations were obtained from 11 donors between January 1993 and September 1997. 270 samples were cryopreserved and 1,399 straws obtained from 120 ejaculates were used in 495 insemination cycles. 52 pregnancies were achieved in 128 recipients (40.6%). No significant differences were found between donors of high fecundability and those of low fecundability regarding sperm parameters. The mean donor fecundability index was 10.5%. The optimal and suboptimal samples yielded similar results. Donors with suboptimal semen quality had an increased number of samples rejected after thawing. Traditional semen analysis parameters do not differentiate high from low fecundability donors. Suboptimal results of the semen analysis should not exclude potential donors from an artificial insemination donor (AID) program.