Hepatitis A virus (HAV) infection is often a self limiting disease and infects millions of people worldwide every year. HAV infection is one of the most important public health problems all over the world, especially in areas with high prevalence rate of HAV. Seroprevalence of HAV infection shows great differences not only between different countries but also between different regions in the same country. It is inversely related to the level of socioeconomic status, sanitation and personal hygiene. The objective of this study was prevalence of Hepatitis A virus (HAV) on Jeddah population, Saudi Arabia. Also find out the relationship of our result with age, gender and ethnicity. Serum samples were collected from studied population between 2 and 35 or more years of age and stratified into the following age groups: 2 to 5, 6 to 9, 10 to14, 15 to19, 20 to 24, 25 to 29, 30 to 34 and more than 35 year, Serum samples were not available for less than 2 year of age. Serum samples also were stratified according to nationality into Saudi and non Saudi. And according to sex serum samples were stratified into male and female. Prevalence was calculated separately for each age group, for male and female separately, and for studied population as a whole. Sample sizes were calculated to achieve a 95% confidence interval (CI) of approximately ±5% for each age group. The determination of anti-HAV antibodies was carried out by ELISA-test.For all age groups, there was no significant difference between genders regarding anti-HAV seropositivity. The prevalence of IgG antibodies to HAV was 33.1% overall, 33.6% among males and 32.5% among females with no statistically significant difference (P>0.05). However, it increased significantly with the age. The IgG antibodies to HAV were found in 20.3 % of Saudi population, and 49% of non Saudi population (p<0.05). There was significant difference between nationality regarding anti-HAV seropositivity. The prevalence of HAV among adult population (39.3%) was higher than among children population (22.4%). The chi-square test showed significant differences in the prevalence of HAV between adult and children population (p<0.05).