Many hepatitis C virus (HCV)-infected individuals do not have any obvious risk factors and one of the putative sources of infection may be inadvertent exposure to infected blood or body fluids in the clinical setting. The aim of this study was to assess the role of medical procedures in transmission of hepatitis C in north-eastern Poland. In total, 194 patients with chronic hepatitis C were eligible for the study. The control group consisted of 275 age- and sex-matched individuals. Patients with a history of intravenous drug use were excluded. On multivariate analysis, transfusions [odds ratio (OR) = 3.7, 95% confidence interval (CI) 2.2-6.3], minor surgery (OR = 3.2, 95% CI 1.5-6.7) and dental care (OR = 2.3, 95% CI = 1.4-4.0) were independently associated with HCV infection. We conclude that apart from transfusion, minor medical procedures and dental care may carry a significant risk of hepatitis C infection. Improvements in basic hygiene routines and strict adherence to universal precautions may be essential to prevent iatrogenic transmission of the infection.