Intrauterine insemination (IUI) is a method for the treatment of marital infertility involving the intrauterine or fallopian deposition of washed spermatozoa, depending on the amount of inseminated semen. In view of the divergent opinions about the inseminated volume, the objective of this study was to compare the two techniques (3.0 mL or 0.5 mL) in two groups of patients.We performed 164 cycles of ovulation induction followed by IUI. The patients were divided into two groups according to the technique used. Group low volume--50 cycles and 0.5 mL of inseminated semen; Group high volume--114 cycles and 3.0 mL of inseminated semen. The cycle was monitored on the basis of endometrial thickness and follicular development measured by transvaginal ultrasound. Human chorionic gonadotrophin (hCG) was administered in the presence of a follicle measuring 18 mm in mean diameter. The procedure was performed after sperm washing using a discontinuous PureSperm gradient, 40 h later.We obtained a similar clinical pregnancy rate for the two groups (14.0% for Group low volume and 15.7% for Group high volume). There was one abortion in each group. We detected no interference by any etiology of infertility or by the total motile recovered sperm with pregnancy rate.The results did not demonstrate superiority of one method over the other, with both therapeutic alternatives being satisfactory for the treatment of infertile couples.