HIV-infected persons are at risk for HBV co-infection which is associated with increased morbidity and mortality. Unfortunately, protective immunity following HBV vaccination in HIV-infected persons is poor. This randomized, phase II, open-label study aimed to evaluate efficacy and safety of 40mcg HBV vaccine with or without 250mcg GM-CSF administered at day 0, weeks 4 and 12. HIV-infected individuals ≥18 years of age, CD4 count ≥200cells/mm3, seronegative for HBV and HCV, and naïve to HBV vaccination were eligible. Primary endpoints were quantitative HBsAb titers and adverse events. The study enrolled 48 subjects. Median age and baseline CD4 were 41 years and 446cells/mm3, 37 were on ART, and 26 subjects had undetectable VL. Vaccination was well tolerated. Seven subjects in the GM-CSF arm reported transient grade ≥2 signs/symptoms (six grade 2, one grade 3), mostly aches and nausea. GM-CSF had no significant effect on VL or CD4. Four weeks after vaccination, 26 subjects (59%) developed a protective antibody response (HBsAb ≥10mIU/mL; 52% in the GM-CSF arm and 65% in the control arm) without improved Ab titer in the GM-CSF vs. control arm (median 11mIU/mL vs. 92mIU/mL, respectively). Response was more frequent in those with CD4 ≥350cells/mm3 (64%) than with CD4 <350cells/mm3 (50%), though not statistically significant. GM-CSF as an adjuvant did not improve the Ab titer or the development of protective immunity to HBV vaccination in those receiving an accelerated vaccine schedule. Given the common routes of transmission for HIV and HBV, additional HBV vaccine research is warranted. © 2010 Elsevier Ltd.