OBJECTIVE: To compare the efficacy of intracervical insemination (ICI), intrauterine insemination (IUI), and a combination of intratubal and intrauterine insemination (ITI/IUI) for donor insemination. DESIGN: Prospective randomized clinical trial. SETTING: The University of Michigan donor insemination program. PATIENTS, PARTICIPANTS: Forty-one women undergoing donor insemination with cryopreserved sperm for either isolated male factor or male factor plus ovulatory dysfunction corrected by clomiphene citrate. INTERVENTION: Each patient was randomly assigned to receive each of the three insemination techniques in consecutive cycles until pregnancy occurred or the patient dropped from the study. MAIN OUTCOME MEASURES: Cycle fecundity rates were compared using the chi 2 test, and cumulative pregnancy rates (PRs) determined by life table analysis were compared using a log-rank test. RESULTS: Cycle fecundity rate was significantly higher for IUI (18.3%) than for ICI (3.9%) or ITI/IUI (7.3%). By life table analysis, the cumulative PR for IUI was significantly higher than for ICI, but the PR for ITI/IUI was not. CONCLUSION: For donor insemination with cryopreserved sperm, IUI increases cycle fecundity compared with ICI. The addition of ITI to IUI, however, interferes with the apparent beneficial effect of IUI alone.