['To compare the main outcome of IUI with the Gynetics catheter (Gynetics Medical Products, Hamont-Achel, Belgium) or the Makler cannula (Sefi-Medical Instruments, Haifa, Israel).', 'Prospective, randomized study.', 'Infertility and endocrinology unit in a university hospital.', 'Two hundred fifty-one infertile couples undergoing 784 consecutive IUI treatments.', 'Patients were randomly assigned to undergo IUI treatment with either the Gynetics catheter (124 patients) or the Makler cannula (127 patients).', 'Primary outcome measures were pregnancy and cumulative pregnancy rates. Secondary outcome measures were the ease of introduction of the catheter, the presence of bleeding, and semen regurgitation after removal of the catheter.', 'The use of the Gynetics catheter resulted in similar pregnancy (10.4% vs. 9.7%) and cumulative pregnancy rates (27.9% vs. 26.4%) as compared with the Makler cannula. Difficult introduction of the catheter was more frequent in the Gynetics group than in the Makler group (19.4% vs. 8.0%, respectively), but the frequency of bleeding did not differ between groups. Sample regurgitation was observed more often in the Makler group than in the Gynetics group (49.9% vs. 17.9%, respectively).'] Does catheter type affect the outcome of intrauterine insemination treatment : a prospective randomized study?