A total of 143 medical students participated in a serological and immunization coverage survey in Geneva. Between 29 and 54% had not received the 6 injections recommended in Switzerland against tetanus, diphtheria and poliomyelitis. The vaccination rates remain low against measles (57%), rubella (46%) and mumps (11%). Satisfactory levels of antibodies against measles were detected in all students. Between 4 and 6% did not have antibodies against mumps, varicella and rubella. Only 5.4% of Swiss medical students had antibodies against hepatitis A. HBc antibodies were present in 4% of the students. Medical students are at risk of contracting and transmitting vaccine preventable diseases. Swiss medical schools should play a leading role in the development of screening programs encouraging immunization of students entering university.