In general, the prevalence and genotype distribution of hepatitis C virus (HCV) are estimated based on the ambulatory clinic or hospital population. In the present work, a population-based study was conducted to estimate the prevalence of HCV infection in Salvador, Brazil. A total of 1308 serum samples were collected from 30 "sentinel areas", and the prevalence of HCV infection was determined by ELISA and confirmed by recombinant immunoblot assay and RT-PCR. The overall prevalence of HCV infection was 1.5% (20/1308). Prevalence was greater among those aged 35 years or older and those with more education. Genotype 3 was the most common (53.3%), followed by genotypes 1 (40%) and 2 (6.7%). These observations are different from those found in a prior survey of hospital and ambulatory patients in Salvador, who were most frequently infected with genotype 1, followed by genotypes 3 and 2, respectively.