OBJECTIVE This study aimed to evaluate the clinical pregnancy rate of intrauterine insemination cycles in relation to patient age, cause of infertility, ovulation induction method, number of mature follicles and sperm with progressive motility. METHODS This retrospective observational study included 237 intrauterine insemination cycles performed from 2011 to 2015 at the Assisted Reproduction Service of the Hospital das Clínicas of the Ribeirão Preto Medical School, University of São Paulo. Student's t-test was used to compare quantitative variables and the chi-square test was used to compare qualitative variables. RESULTS Patient age was inversely and significantly correlated with pregnancy rates (p=0.001) (Pregnant women = 32.56±5.64 years, non-pregnant women = 36.64±5.03 years). Cause of infertility, ovulation induction method, number of mature follicles and sperm with progressive motility were not associated with pregnancy rates. The overall clinical pregnancy rate was 7.59%. In the subgroup of patients (n=102 cycles) considered ideal for intrauterine insemination (age ≤35 years, unexplained infertility, ovarian factor infertility or minimal endometriosis, and a partner with sperm count ≥2.5 × 106 retrieved on the day of insemination) the pregnancy rate was 12.74%. CONCLUSIONS In the studied group, female patient age was the only variable significantly correlated with intrauterine insemination success rates.