OBJECTIVE To compare the efficacy of IUI donor and pericervical insemination donor in frozen sperm insemination cycles under gonadotropin stimulation. METHODS Couples where infertility was caused by male conditions were randomized into two groups: IUI and pericervical insemination. Semen samples, gonadotropin stimulation, and ovarian monitoring were the same in both groups. One IUI was performed per cycle as against two pericervical inseminations. METHODS The donor insemination program at the Human Reproduction Unit at the Hospital of Cruces, Pais Vasco University. METHODS Eighty-eight women (47 IUI and 41 pericervical insemination) with at least one patent fallopian tube and < 40 years of age. METHODS Intrauterine gestational sac observed by transvaginal ultrasound. RESULTS Per woman pregnancy rate (PR) was higher in IUI than in pericervical insemination (65.96% versus 41.46%, odds ratio [OR] = 2.73, confidence interval [CI] = 1.06 to 7.2). Pregnancy rates were always higher in IUI irrespective of woman and husband's status, but statistical significance was not reached in any subgroups analyzed independently. Per cycle PR was also significantly higher in IUI than in pericervical insemination: 24.03% (31/129) versus 11.89% (17/143) (OR = 2.34, CI = 1.17 to 4.71). Moreover, cumulative PR was higher in IUI (86% versus 49.5%) (OR = 6, CI = 1.98 to 18.80). CONCLUSIONS Per woman and per cycle PRs were significantly higher in IUI.