The study aimsed at surveying and analysing the prevailing risks for medical students due to so-called needlestick injuries, I. e., injuries to the skin by handling sharp objects by which blood of patients can be transmitted to the health professional. After introducing preventive measures in a typical German university hospital, a total of 1 903 students of human medicine in their clinical period from 2009 to 2012 (from a total of 2 024 subjects - a rate of 94.0%) were questioned in detail about potential needlestick or other injuries related to their work. The results show that such injuries happen particularly during the clinical period of the medical studies: While only 20.6% of the students indicated a needlestick injury at the beginning of this period, half of the students (50.9%) had experienced at least one injury at the end of the clinical period. The activities mentioned most frequently were taking of blood samples and injections. Needlestick injuries happened most frequently in surgical units, in internal medicine, and in gynaecology. Accidents happened mostly during secondary employment, medical traineeship, or in the context of practical nursing. In consequence, measures for improvement of the primary prevention should start with training on the one hand: Only briefing seems to be insufficient - intensive exercises in using stick-proof instruments seems to be more promising. On the other hand, the comprehensive introduction of stick-proof instruments has to be supported.