In the present retrospective study we compare the efficacy of gonadotropin-releasing hormone (GnRH) agonist in a long protocol and a GnRH agonist in a short protocol administration for controlled ovarian hyperstimulation (COH) in an ICSI program. A total of 424 consecutive patients with a history of male factor were included in the present study. Three hundred and three patients were included in the long protocol and 121 in the short protocol. Patients treated with the short protocol were stimulated in a shorter time and achieved lower estradiol levels. A significantly higher percentage of oocytes transferred were found in the long protocol. The clinical pregnancy rate per embryo transfer was 39.3% in the long protocol and 19.2% in the short protocol (p=0.001).