Mixing an oligoasthenospermic husband's semen with that of a donor prior to insemination (AIM) has been criticized, since such semen may contain antibodies which could interfere with normal sperm function. The efficacy of AIM was reviewed in 227 patients who underwent AI with frozen donor semen. Thirty-four patients requested AIM and thirteen conceived (38.2%). Seven who failed to conceive after AIM changed to donor insemination (AID), and two conceived. One hundred and ninety-three patients had AID alone, and eighty conceived. Thus, 200 patients had AID, with 82 pregnancies (41%). There were no significant differences between the AIM and AID groups with regard to age, prior fertility, and additional infertility factors. The conception rates between groups were not significantly different. Pregnancy rates per cycle of AI and dropout rates were also similar. Postinsemination testing after AIM did not reveal any effect of husband's semen upon donor spermatozoa. This study failed to show a deleterious effect of semen from azoospermic or oligoasthenospermic, infertile men upon normal semen, as used in AIM.