We assessed the antibody levels and risk factors for tetanus in an adult population in the Kocaeli Region of Turkey. In 595 individuals over 20 years of age, serum concentrations of anti-tetanus antibodies were detected by enzyme-linked immunosorbent assay and a brief questionnaire was administered. The overall immunity rate was approximately 80% and there was a progressive decline in protection with increasing age. Antibody levels were significantly higher in educated people (80.1%), in employed people (90.3%), in those under 40 years of age (95.0%) and in those who stated that they had received a previous tetanus vaccination (87.9%). There was no association between antibody level and sex, residence, socioeconomic status, military status or history of injury. These data indicate that a vigorous post-injury prophylaxy with antitoxin and antisera should be put into practice, especially for older people, and that immunization programs applied every 10 years must be strengthened.