Background: Simulation-based training is increasingly used to acquire basic laparoscopic skills. Multiple factors can influence training, e.g., distributed practice is superior to massed practice in terms of efficiency. However, the optimal interval between training sessions is unclear. The objective of this trial was to investigate if shorter intervals between sessions are more efficient than longer intervals during proficiency-based laparoscopy simulator training. Methods: A randomized simulation-based trial where medical students (n = 39) were randomized to proficiency-based training with either 1–2 days (intervention group) or 6–8 days (control group) between training sessions. Both groups practiced a series of basic tasks and a procedural module until proficiency level on the LapSim® simulator. Both groups were given instructor feedback upon request. After reaching proficiency, participants were invited back for a retention test 3–5 weeks later and practiced the same tasks to proficiency again. Results: The mean time to reach proficiency during training was 291 (SD 89) and 299 (SD 89) min in the intervention and control group, respectively (p = 0.81). During the retention test, the mean time to reach proficiency was 94 (SD 53) and 96 (SD 39) minutes in the intervention and control groups, respectively (p = 0.91). Conclusion: We found no difference whether practicing with shorter intervals or longer intervals between training sessions when examining time to proficiency or retention.