Hepatitis A is a widespread infectious disease. The prevalence of the disease is closely related to socioeconomic status (SES) and environmental factors. Understanding its prevalence is essential for instituting appropriate precautions. The aim of this study was to determine the prevalence of hepatitis A and evaluate the associated demographic features in children and young adults in Istanbul. In total, 630 individuals between the ages of 5-24 were included in the study. They were classified into four age groups (5-9, 10-14, 15-19 and 20-24 years). The seropositivity of hepatitis A in the whole study population was 40%. Age-specific prevalence was 11.4% in children 5-9 years old, 29% in those 10-14 years old, 49.7% in those 15-19 years old and 69% in those 20-25 years old. Seropositivity was associated with increasing age, low SES, large family size, low maternal educational level, use of unsafe drinking water and living in regions with poor infrastructure and incomplete urbanization. When we compared our results with previous seroprevalence studies performed in Istanbul, we found an epidemiological shift towards increasing age. Factors associated with changes in prevalence were urbanization and associated infrastructure improvement, knowledge of the disease by the population, use of good hygiene and use of vaccination in those at high risk.