Much is still to be learned about the assessment of simulation-based surgical skills training. However, assessing surgery skills through simulation is a new horizon in medical education. Providing a safe environment for surgical residents to assess their performance rigorously without placing patients in jeopardy is valuable. Using simulators (both warm and cold) as a means to assess trainees has been established. However, also problems concerning the validity and reliability of such simulation-based assessment tools exist, particularly in surgery, that may need to be investigated even more to decide whether to use them as a tool for assessing the performance of surgical residents.