To examine the effect of recipient body mass index (BMI) on IVF outcomes in fresh donor oocyte cycles.Retrospective cohort study.Not applicable.A total of 22,317 donor oocyte cycles from the 2008-2010 Society for Assisted Reproductive Technology Clinic Outcome Reporting System registry were stratified into cohorts based on World Health Organization BMI guidelines. Cycles reporting normal recipient BMI (18.5-24.9) were used as the reference group.None.Implantation rate, clinical pregnancy rate (PR), pregnancy loss rate, live birth rate.Success rates and adjusted odds ratios with 95% confidence intervals for all pregnancy outcomes were most favorable in cohorts of recipients with low and normal BMI, but progressively worsened as BMI increased.Success rates in recipient cycles are highest in those with low and normal BMI. Furthermore, there is a progressive and statistically significant worsening of outcomes in groups with higher BMI with respect to clinical pregnancy and live birth rate.