Objectives: Clomiphene citrate-intrauterine insemination (CC-IUI) cycles are often recommended by physicians as a first line therapy for infertile couples. This treatment is also often requested by patients who are reluctant to proceed with gonadotropin-IUI or in-vitro fertilization-embryo transfer cycles due to concerns about financial cost or the higher risks of multiple pregnancy and ovarian hyperstimulation syndrome. The objectives of this study were to determine if treatment success could be predicted by: 1) patient characteristics prior to treatment or 2) individual cycle parameters.Design: Retrospective chart review of all patients (68 patients, 135 cycles) treated with CC-IUI at a single academic infertility center over a one-year period.Materials and Methods: Patients were treated with CC at doses of 50–150 mg daily on cycle days 5–9, with vaginal ultrasounds performed every 2–4 days starting on cycle day 10. When one or more follicles had a mean diameter of ≥18 mm, ovulation was triggered with HCG 5,000 IU IM 38–40 hours prior to IUI. Sperm were prepared using density gradient centrifugation, and IUI performed with a Tomcat catheter. Luteal support consisted of HCG 2,500 IU IM 6 days after the first injection. Livebirth after 24 weeks of pregnancy (LB) was the sole outcome measure. Charts were reviewed to evaluate: 1) pre-cycle patient characteristics: infertility diagnosis, presence of ovulatory dysfunction, female age, presence of male factor, # of previous treatment cycles, and parity; and 2) individual cycle parameters: # of follicles ≥16 mm on day of HCG, endometrial thickness, total # of motile sperm inseminated, and use of donor sperm. Logistic regression or Chi square were used to analyze data as appropriate.Results: Over 12 months, eleven LB occurred in 68 patients (16.1%) undergoing 135 cycles (8.1%). Only female age significantly predicted treatment success: in women ≤34 yrs, LB occurred in 10/84 cycles (11.9%) vs. 1/51 cycles (1.9%) in patients ≥35 yrs (P<0.05). No other patient characteristics nor any individual cycle parameters were predictive of treatment success.Conclusions: CC-IUI was a highly effective therapy for women aged ≤34 yrs; it was clearly unhelpful for those ≥35 yrs and should be discouraged in these women. Objectives: Clomiphene citrate-intrauterine insemination (CC-IUI) cycles are often recommended by physicians as a first line therapy for infertile couples. This treatment is also often requested by patients who are reluctant to proceed with gonadotropin-IUI or in-vitro fertilization-embryo transfer cycles due to concerns about financial cost or the higher risks of multiple pregnancy and ovarian hyperstimulation syndrome. The objectives of this study were to determine if treatment success could be predicted by: 1) patient characteristics prior to treatment or 2) individual cycle parameters. Design: Retrospective chart review of all patients (68 patients, 135 cycles) treated with CC-IUI at a single academic infertility center over a one-year period. Materials and Methods: Patients were treated with CC at doses of 50–150 mg daily on cycle days 5–9, with vaginal ultrasounds performed every 2–4 days starting on cycle day 10. When one or more follicles had a mean diameter of ≥18 mm, ovulation was triggered with HCG 5,000 IU IM 38–40 hours prior to IUI. Sperm were prepared using density gradient centrifugation, and IUI performed with a Tomcat catheter. Luteal support consisted of HCG 2,500 IU IM 6 days after the first injection. Livebirth after 24 weeks of pregnancy (LB) was the sole outcome measure. Charts were reviewed to evaluate: 1) pre-cycle patient characteristics: infertility diagnosis, presence of ovulatory dysfunction, female age, presence of male factor, # of previous treatment cycles, and parity; and 2) individual cycle parameters: # of follicles ≥16 mm on day of HCG, endometrial thickness, total # of motile sperm inseminated, and use of donor sperm. Logistic regression or Chi square were used to analyze data as appropriate. Results: Over 12 months, eleven LB occurred in 68 patients (16.1%) undergoing 135 cycles (8.1%). Only female age significantly predicted treatment success: in women ≤34 yrs, LB occurred in 10/84 cycles (11.9%) vs. 1/51 cycles (1.9%) in patients ≥35 yrs (P<0.05). No other patient characteristics nor any individual cycle parameters were predictive of treatment success. Conclusions: CC-IUI was a highly effective therapy for women aged ≤34 yrs; it was clearly unhelpful for those ≥35 yrs and should be discouraged in these women.