Despite the lack of any scientific data, many ART programs split the daily gonadotropin dose during ovarian stimulation, while others give the entire dose during a single administration, usually at night. Prospective randomized. 213 women undergoing IVF/ICSI cycles at a single private ART center. Gonadotropin administration once daily compared to twice daily. Gonadotropin usage, clinical and ongoing PR RESULTS: There were 110 women in the once daily compared to 103 in the twice daily arm. All cycles were blastocyst transfers. There was a significantly lower FSH use in the once daily arm compared to the twice daily arm (1507.5 ± 517.5IU vs. 1702.5 ± 622.5, P = 0.015), and a trend towards lower hMG use in the once daily arm (1342.5 ± 562.5IU vs. 1462.5 ± 645.0, P = 0.15), without compromising clinical pregnancy rate (PR) (71.8% vs. 70.9%, P = NS) or delivery/ongoing PR (58.2% vs. 62.1%, P = NS). There were no differences in age, body mass index (BMI), peak estradiol, peak progesterone, retrieved oocytes, fertilized oocytes, number of ET, or PR. Once daily administration is associated with lower gonadotropin usage without compromising success rates.