In the course of clinical training medical students are in particular exposed to infectious diseases. Therefore, the present study was performed to investigate the immunity status of 223 medical students in their first clinical semester to job-related diseases. Specific serological antibody testing of hepatitis B-virus (HBV), hepatitis C-virus (HCV), human immunodeficiency virus (HIV), varicella zoster- (VZV), measles-, mumps-, rubella and polioviruses' type 1, 2 and 3 were performed. The results yielded, that 69.5% of the students had an anti-HBs-level > or =10 IU/l and 54.7% > or =100 IU/l. Neither HCV infection nor HIV infection were found, but one student showed an active HBV infection. Virus specific immunity rates were found in 91.5% for measles, 80.3% for mumps, 90.1% for rubella and 96.9% for varicella. Furthermore the medical students demonstrated neutralizing antibodies to polioviruses: 95.1% (type 1), 96.9% (type 2) and 70% (type 3). 68.2% had antibodies (titer 1:> or =10) against all three virus types. The partly significant gaps of immunity in the students need to be closed prior to the first contact with patients.