OBJECTIVES: To estimate whether training on previously validated laparoscopic skill stations translates into improved technical performance in the operating room.; METHODS: We performed a multicenter, randomized, controlled trial evaluating the performance of a laparoscopic bilateral midsegment salpingectomy. Residents were randomized to either traditional teaching (no simulation) or faculty-directed sessions in a simulation laboratory. A sample size of at least 44 lower-level residents (postgraduate year [ PGY] 1 or 2) and 66 upper-level (PGY 3 or 4) were necessary to demonstrate a 50% improvement in performance assuming an a error of 0.05 and beta error of 0.20 for each group independently. The primary outcomes were the final total normalized simulation score and the operating room performance score. Paired t test and Wilcoxon rank-sum tests were used to evaluate the differences within and between cohorts. Our final model involved a multiple linear regression analysis for the main effects of a priori-specified variables.; RESULTS: We enrolled 116 residents from eight centers across the United States. There was no statistically significant difference in baseline simulation or operative performances. Although both groups demonstrated improvement with time, the trained group improved significantly higher normalized simulation scores (378 +/- 54 compared with 264 +/- 86; P<.01) and higher levels of competence on the simulated tasks (96.2% compared with 61.1%; P<.01). The simulation group also had higher objective structured assessment of technical skills scores in the operating room (27.5 compared with 30.0; P=.03).; CONCLUSION: We found that proficiency-based simulation offers additional benefit to traditional education for all levels of residents. The use of easily accessible, low-fidelity tasks should be incorporated into formal laparoscopic training.