In order to find out the variations in the Prevalence of HAV ab and identify the persons who should be vaccinated against Hepatitis A virus, we assessed HAV ab to 200 patients without any occupational risk. They were classified by their socioeconomic status; in the following categoris: High (level I n = 0); Medium-High (level II n = 50); Medium-Low (level III, n = 50); Low (level IV, n = 50); and Very Low (level V, n = 50). The percentage of positivity ofr serum HAV ab was: Level II: 12%, Level III: 18%, Level IV: 38% and Level V: 40%. The difference between levels II and III and between levels IV and V was no significant (p > 0.05), but after making a comparation between levels II and III as a group and levels IV V as another one, we found a statistical significant difference (p < 0.005). We concluded: There is a bimodal behavior for the prevalence of serum HAV ab in our study: one group with high prevalence (78%) and another one with low prevalence (30%). The massive Vaccination government programs and the vaccionation in particular cases in the daily medical practice should be done after assessing the personal Socioeconomic status in order to improve the use of this tool and achieve a progressive reduction in the morbiditi and high endemicity of HAV in our city.