Prior work experience in a relevant medical profession is an important admission criterion currently used at many German medical schools in addition to cognitive criteria. In other countries, work experience is often considered in later admission stages (e.g., interviews with pre-selected subgroups of applicants). However, evidence for its predictive validity for study success in addition to cognitive admission criteria is currently lacking. We therefore assessed whether completed vocational training in a relevant medical profession can predict study performance in the first two years of study in addition to cognitive admission criteria. Admission and study performance data of all currently enrolled medical students at two German medical schools (Göttingen and Heidelberg) beginning with the 2013/14 cohort were retrospectively analyzed. Cognitive admission criteria in our sample were GPA grades and a cognitive test ("Test für Medizinische Studiengänge", TMS). We defined the study outcome parameter as the mean percentile rank over all performance data points over the first two years of study for each location, respectively. A multi-level model with varying intercepts by location, GPA, TMS, vocational training, and sex as predictors accounted for 14.5% of the variance in study outcome. A positive predictive association with study outcome was found for vocational training ([beta] = 0.33, p = 0.008) beyond GPA ([beta] = 0.38, p < 0.001) and TMS ([beta] = 0.26, p < 0.001). Our results support the use of prior vocational training as a selection criterion for medical studies potentially adding predictive validity to cognitive criteria.