en Pediatric Pediatric Original Research Original Research In order to determine the efficacy of recombinant hepatitis B vaccine in Iranian infants, we analyzed the efficacy of a recombinant hepatitis B vaccine in 115 infants aged 12-24 months born to HBsAg negative mothers who received three doses of HBV Antibody to hepatitis B surface antigen (anti-HBs) was checked after the third dose of the vaccine, 94.8% of the infants had developed protective antibody levels. The vaccine was well-tolerated and no serious adverse effects were reported. This study is in agreement with a WHO report which recommends that the easiest and most cost-effective strategy for the control and eventual eradication of HBV would be to immunize all newborns with hepatitis B vaccine only [World Health Organization report, 1984]. hepatitis B vaccine, infant, efficacy, immunization. 347 349 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-298-289&slc_lang=en&sid=1 A ZAMANI 20031947532846004276 20031947532846004276 Yes From the Departments of Pediatrics School of Medicine, Tehran University of Medical Sciences, Tehran, I.R. Iran. H SHAJARI 20031947532846004277 20031947532846004277 No From the Departments of Neonatology, School of Medicine, Tehran University of Medical Sciences, Tehran, I.R. Iran. I SEDIGHY 20031947532846004278 20031947532846004278 No From the Departments of Pediatrics School of Medicine, Tehran University of Medical Sciences, Tehran, I.R. Iran.