Hepatitis B virus (HBV) is a blood borne and sexually transmitted virus. Rates of new infection and acute disease are high among adults, but chronic infection is more likely to occur in persons infected as infants or young children aged 2-5 years old. Hepatitis B vaccination is the most effective measure to prevent HBV infection and its consequences. This study was aimed to evaluate the effectiveness of HBV vaccine in randomly selected children from Misurata province, Libya and personal factors associated with serologic evidence of the immune response.  Serum samples for each participant were tested for the quantitative determination of anti-HBs antibody using Enzyme Linked Fluorescent Assay. The results of antibody response to hepatitis-B vaccine among children cases included in the current study indicated that antibody decay occurred with time. In our study negative antibody response were observed in 21% and 17% among male and female children, respectively whom were vaccinated according to the official vaccination schedule and their ages range was 2-5 years old. These negative percentages were increased to 27% and 29% in male and female children, respectively whom age range was 6-8 years old. While the percentages were 33% and 25% in male and female children, respectively of age ranged from 9-12 years old. Antibody prevalence titer was higher in older male and female children than younger children as the antibody titers were 33, 25; 27,29; and 21, 17 respectively.