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Introduction & Objective: The risk of developing chronic hepatitis B virus (HBV) is 5% in general population but can reach up to 20% in HIV patients. The response rate to HBV vaccine in HIV infected patients is 23.8-56 percent. The aim of this study was to evaluate response of HIV-infected patients to 20 µg dose of recombinant HBV vaccine. Materials & Methods: In this quasi experimental study, 51 subjects, sampled through census, were HIV patients who had HBsAg negative test in HIV/AIDS counseling and care center. Patients were vaccinated with 20 µg of recombinant HBV vaccine, IM at intervals of 0, 1 and 6 months. Response to the vaccine was checked 2 months after the last injection. Data were analyzed with SPSS software, using descriptive statistics and nonparametric tests. Results: The mean age of the patients was 33.68±8.37 years. Two patients were female (3.9%) and 49 patients were male (96.1%). Mean of hepatitis B antibody level was 47.55±71.58 mIU/ml. The levels of antibody in different patients were as follow: 31 patients (60.8%) <10 mIU/ml and 20 patients (39.2%)> 10 mIU/ml. There was no significant correlation between antibody levels and CD4+ cell count (correlation coefficient = -0.191). Conclusion: Response to hepatitis B vaccination is low in HIV infected patients. Conventional dose of HBV vaccine is not enough to get protective immunity. Therefore, two-fold dose of vaccine dose, repeat of conventional dose or increasing of interval administration of hepatitis B vaccine should be considered in future studies.