BackgroundTo improve patient safety, educational interventions on all system levels, including medical school are necessary. Sound theoretical knowledge on elements influencing patient safety (such as error management or team work) is the basis for behavioral changes of health care professionals.MethodsA controlled, quasi-experimental study with repeated measures was deployed. The intervention group participated in a mandatory e-learning course on patient safety (ELPAS) between October 2016 and December 2016. The control group did not receive any didactic session on patient safety. In both groups we measured technical knowledge and attitudes towards patient safety before the intervention (T0), directly after the intervention (T1) and one year after the intervention (T2). Participants were 309 third-year medical students in the intervention group and 154 first- and second-year medical students in the control group.ResultsTechnical knowledge in the intervention group (but not the control group) improved significantly after the intervention and remained high after one year (F(2, 84) = 13.506, p < .001, η2 = .243). Students of the intervention group felt better prepared for safe patient practice, even one year after the intervention F(2, 85) = 6.743, p < .002, η2 = .137). There was no sustainable significant effect on attitudes towards patient safety.ConclusionThis study shows, that eLearning interventions can produce significant long-term effects on patient safety knowledge, however, the study did not show long-term effects on attitudes towards patient safety. Our study implies two potential developments for future research: e-learning might be used in combination with face-to-face sessions, or more intensive (in terms of frequency and duration) e-learning sessions may be needed to achieve lasting changes in attitude.