The aim of this study was to assess skill retention in the operating room following completion of a proficiency-based laparoscopic skills curriculum. Novices (n = 15) were randomized to a control and a training group that practiced to proficiency on the Fundamentals of Laparoscopic Surgery suturing model. The performance of both groups was assessed on the simulator and on a live porcine laparoscopic Nissen fundoplication model at training completion (posttest) and 5 months later (retention test). Training to proficiency required 4.7 +/-1.2 hours and 41 +/- 10 repetitions. Trained participants outperformed controls, and their performance deteriorated slightly between posttests and retention tests on the simulator (505 +/- 22 vs 462 +/- 50, respectively; P < .05) but not in operating room (263 +/- 138 vs 279 +/- 88, respectively; P = .38). Proficiency-based simulator training results in durable improvement in operative skill of trainees even in the absence of practice for up to 5 months. Minute simulator performance changes do not translate to the operating room.