Our objective was to evaluate the effect of a change in treatment protocols, suggested following an inspection visit by the regulatory authority, from single to double inseminations during donor insemination treatment cycles. We therefore conducted a retrospective audit of pregnancy rates in the reproductive medicine clinic of a major teaching hospital. All patients were treated for male factor infertility by donor insemination, without ovulation induction with gonadotrophins between October 1992 and December 1995. The main outcome measures were cumulative conception and live birth rates. During the study period 250 patients underwent treatment and 650 single insemination and 277 double insemination treatment cycles were undertaken. The pregnancy rate per cycle was 0.054 and 0.119 for single and double insemination respectively. After six cycles the cumulative pregnancy rates were 0.28 and 0.47 and the take-home baby rates were 0.25 and 0.37 for single and double inseminations respectively. The change in practice from single to double insemination resulted in a doubling of the pregnancy rate per treatment cycle. Cumulative pregnancy rates after two treatment cycles of double insemination were comparable with those achieved after six cycles of single insemination. These results have significant implications for both patients and purchasers.