The purpose of this study was to analyze the relationship between the reproducibility of holmium laser enucleation of the prostate (HoLEP) and prostate size over the learning curve. We compared the outcome among three institutions in three subgroups on the basis of the weight of tissue retrieved. There were no significant differences in operating time, efficiency of the procedure, decrease in hemoglobin level and postoperative urinary incontinence among three institutions, only in patients with prostates >or=20 g-<40 g retrieved. Our data indicate that HoLEP is more reproducible in patients with a moderate-sized prostate over the learning curve.