Background: Hepatitis B vaccination is necessary to prevent infection with this virus and to prevent the development of chronic hepatocellular carcinoma. Materials and Methods: Assessing the immunization status after receiving the vaccine and identifying non-respondents, especially among health care workers and physicians, is important because of the higher risk of contact with infected patients and their body fluids. In this study, the vaccination status of health and medical staff of a children's hospital was investigated to measure the Anti-HBs antibody titer and its relationship with body mass index, smoking, and drugs used in individuals with underlying diseases. In this study HBsAb kit, DIA. PRO,Italy was used to measure the antibody titers. Statistical analysis was done using SPSS software version 26. Results: The results of this study showed that a proper antibody titer is present in 66. 6% of the participants. Reduced antibody titers to unsafe levels were measured among the employees older than 50 years, smokers, and employees with low or very high body mass index. Conclusion: In this study, the decrease in antibody titer did not show any association with underlying diseases and related medications. The presence of an unsafe antibody titer among young vaccinated staff suggested additional studies to identify non-responders after receiving a booster dose of the vaccine.