OBJECTIVES: The amount of intense and focused training with the specific goal to improve performance (i.e. deliberate practice) is a predictor of expert-level performance in multiple domains of psychomotor skill learning. Simulation training improves surgical skills in cardiac surgery. We established a training programme that enables early surgical exposure and assessment. We investigated the training effects in coronary surgery simulations in trainees with different levels of surgical experience. METHODS: The early surgical exposure and assessment programme comprises a low- and high-fidelity simulation, self-organized training, instructed workshops and a stepwise challenge increase. Performance was assessed with a multidimensional skill matrix using video recordings. Two groups of trainees [students (N = 7), 1-/2-year residents (N = 6)] completed introductory training (pretraining, level 1) and two 3-week training periods (levels 2 and 3). Fellows (N = 6) served as controls. Residents and students underwent deliberate practice training with specific training targets. Fellows performed regularly scheduled coronary surgery cases. Entry and exit assessments were conducted for levels 2 and 3. RESULTS: Fellows did not improve overall performance. Residents and students showed significant improvements in both technical accuracy and completion times. Residents reached an overall performance level comparable to fellows. Students reached similar accuracy of surgical skills with longer completion times [level 3 exit score/time: fellows 27 (24-29)/min; residents 27 (21-30)/min, P = 0.94; students 17 (17-25)/min, P = 0.068]. CONCLUSIONS: Deliberate practice training resulted in a fast and substantial increase in surgical skills in residents and students. Unexperienced residents reach performance levels of fellows. Deliberate practice simulation programmes should be a mandatory component of surgical training.