We retrospectively analyzed 6,360 artificial insemination cycles of husband's semen through intrauterine insemination (AIH-IUI) or artificial insemination with donor semen through intrauterine insemination (AID-IUI) in patients with infertility between August, 1998 and August, 2010. The relationship between processed total motile sperm count (PTMS) and pregnancy outcome was determined. The study was divided into 6 groups according to PTMS. Group 1: ≤ 2.0 million, Group 2: 2.1-4.0 million, Group 3: 4.1-6.0 million, Group 4: 6.1-8.0 million, Group 5: 8.1-10.0 million, and Group 6: >10.0 million. There was no statistically significant difference in age, duration of infertility, unilateral tubal patency, induced ovulation, and single IUI or double IUI between the 6 groups in both AIH-IUI and AID-IUI. The total clinical pregnancy rate of AIH-IUI was 10.81 % and AID-IUI was 27.52 %. Among the 6 groups, the clinical pregnancy rate was the lowest in Group 1 (P < 0.05) in both AIH-IUI and AID-IUI. With the increased PTMS, the clinical pregnancy rate of IUI was improved. However, a statistical difference between groups was only observed for Group 1. When PTMS is ≤ 2 × 10(6) the clinical pregnancy rate of IUI is significantly decreased. In this case in vitro fertilization (IVF) should be adopted.