We aimed to compare the efficacy of two different starting doses of recombinant follicle stimulating hormone (rFSH), 37.5 vs. 75 international units (IU) for intrauterine insemination (IUI) cycles in non-obese women with polycystic ovary syndrome (PCOS). A total of 109 women who underwent first rFSH stimulated IUI cycle were included in this retrospective cohort study. The primary outcome measure was the clinical pregnancy rate. No significant difference was found in terms of clinical pregnancy rate between the two groups (22% for the 37.5-IU group and 24% for the 75-IU group, respectively,  = .808). There was no significant difference in monofollicular development rate among the groups ( = .354). The total rFSH consumption was lower in the 37.5-IU group compared to the 75-IU group (< .001). There was no statistically significant difference in pregnancy rates between the 37.5-IU and 75-IU groups in both normal weight (BMI: 19-24.9 kg/m) and overweight (BMI: 25-29.9 kg/m) women ( = .889 and .518, respectively). These results suggest that the starting doses of 37.5 and 75 IU of rFSH do not show significant difference in clinical pregnancy rates in non-obese PCOS women undergoing IUI cycles.Impact Statement Low-dose gonadotropin treatment is advised for women with polycystic ovary syndrome (PCOS). However, there are few comparative data on the efficacy of different starting doses of recombinant follicle stimulating hormone (rFSH) for intrauterine insemination (IUI) cycles in PCOS women. There was no statistically significant difference in pregnancy rates of non-obese patients with PCOS having IUI whether rFSH was started at 37.5 or 75 international units (IU). A starting dose of 37.5 IU of rFSH may be a reasonable approach for IUI cycles in non-obese PCOS women.