The optimal assisted reproductive treatment strategy for infertile women with unilateral tubal obstruction remains uncertain. To investigate the role of intrauterine insemination (IUI) in the treatment of infertile women with unilateral tubal occlusion, the data of 148 couples were retrospectively collected and analyzed. Seventy-eight infertile women with unilateral occlusion diagnosed by hysterosalpingography (HSG) were categorized as the study group and 70 others with unexplained infertility as the control group. The study group was divided into a proximal occlusion subgroup and a mid-distal occlusion subgroup for further analysis. The main outcomes, namely the clinical pregnancy rate (CPR), ongoing pregnancy rate (OPR), and live birth rate (LBR) per cycle, were analyzed. Our results showed a tendency of lower CPR, OPR, and LBR in the study group than in the control group, without statistical significance. Further investigations revealed that the unilateral proximal occlusion subgroup had similar CPR, OPR, and LBR as the control group, while the unilateral mid-distal occlusion subgroup had significantly lower CPR (5.1% vs. 20.0%, P=0.035), OPR (5.1% vs. 20.0%, P=0.035), and LBR (5.1% vs. 20.0%, P=0.035) than the control group. In conclusion, the clinical outcomes of IUI were worse in patients with unilateral tubal occlusion than in those with unexplained infertility. This might be primarily caused by the worse outcome of patients with unilateral mid-distal tubal occlusion instead of proximal occlusion.