Of the 1,138 adults in the study, 52% were anti-HAV positive. The anti-HAV prevalence in this study population was 58% higher than the expected prevalence based on age-specific prevalence rates from the general population. Number of years of homelessness (<or =1, 2-4, and>or =5 years) was associated with anti-HAV prevalence (46%, 50%, and 61%, respectively, p<0.001). We found other differences in anti-HAV prevalence (p<0.05) for ever having injected drugs (63% vs