To assess the effects of both male and female body mass index (BMI), individually and combined, on IVF outcomes. Prospective cohort study. University fertility center. All couples undergoing first fresh IVF cycles, 2005-2010, for whom male and female weight and height information were available (n = 721 couples). None. Embryologic parameters, clinical pregnancy, and live birth incidence. The average male BMI among the study population was 27.5 ± 4.8 kg/m(2) (range, 17.3-49.3 kg/m(2)), while the average female BMI (n = 721) was 25.2 ± 5.9 kg/m(2) (range, 16.2-50.7 kg/m(2)). Neither male nor female overweight (25-29.9 kg/m(2)), class I obese (30-34.9 kg/m(2)), or class II/III obese (≥35 kg/m(2)) status was significantly associated with fertilization rate, embryo score, or incidence of pregnancy or live birth compared with normal weight (18.5-24.9 kg/m(2)) status after adjusting for male and female age, partner BMI, and parity. Similar null findings were found between combined couple BMI categories and IVF success. Our findings support the notion that weight status does not influence fecundity among couples undergoing infertility treatment. Given the limited and conflicting research on BMI and pregnancy success among IVF couples, further research augmented to include other adiposity measures is needed.