OBJECTIVE: To compare the results of a minimal-stimulation protocol with those of a standard protocol used for IVF. DESIGN: Retrospective, controlled study. SETTING: University center. PATIENT(S): Fifty-five patients undergoing IVF using a minimal-stimulation protocol with or without adjuvant therapy with a GnRH antagonist. A control group consisted of age- and diagnosis-matched patients undergoing a standard long GnRH agonist (GnRH-a)-gonadotropin stimulation during the same time period. INTERVENTION(S): Clomiphene citrate and gonadotropins, with or without the GnRH antagonist ganirelix. MAIN OUTCOME MEASURE(S): Oocytes recovered and pregnancy rates. RESULT(S): The number of oocytes retrieved was significantly lower for the minimal-stimulation regimen compared with the case of the long GnRH-a protocol (4.8 +/- 2.6 vs. 16.2 +/- 7.5, respectively). The clinical pregnancy rate per transfer, however, was not significantly different between the two regimens (37% vs. 41%, minimal stimulation vs. long GnRH-a protocol, respectively). The addition of ganirelix resulted in at least the same pregnancy outcome as compared with the case of cycles without the antagonist. CONCLUSION(S): Minimal stimulation using clomiphene citrate followed by gonadotropin for IVF results in pregnancy rates equal to the standard long GnRH-a-gonadotropin protocol. The addition of ganirelix resulted in at least similar results with the advantage of eliminating the occurrence of a premature endogenous LH surge.