Objective: To assess skill retention 6 and 12 months after shoulder dystocia training. Methods: Midwives and doctors from six United Kingdom hospitals attended a 40-minute workshop on shoulder dystocia management. Participants managed a standardized simulation before and 3 weeks, 6 months, and 12 months afterward. Outcome measures were delivery, head-to-body delivery time, performance of appropriate actions, force applied, and quality of communication. Results: A total of 122 participants were recruited. One hundred eighteen were evaluated 3 weeks posttraining, for whom follow-up was available for 95 (81%) at 6 months and 82 (70%) at 12 months. Before training, 60 of 122 (49%) achieved delivery, 97 of 118 (82%) were able to deliver after initial training, 80 of 95 (84%) were able to deliver at 6 months, and 75 of 82 (85%) were able to deliver at 12 months. Twenty-one (18%) who could not deliver 3 weeks after training were offered additional training; of these, 11 of 14 (79%) achieved delivery at 12 months. Among those who could deliver 3 weeks posttraining, there was no deterioration in the performance of basic actions, delivery interval, force application, and patient communication. Those who were proficient before initial training performed best at follow-up, but skill retention was also good in those who learned to deliver during initial training. Eighteen percent could not deliver after initial training and required additional individualized tuition; the large majority retained their newly acquired skills at 6 and 12 months. Conclusion: Overall, training resulted in a sustained improvement in performance. Annual training seems adequate for those already proficient before training, but more frequent rehearsal is advisable for those initially lacking competency until skill acquisition is achieved.