Healthy carriers of Haemophilus influenzae type b (Hib) play an important role in the spread of invasive disease. The aim of this study was to assess the need for Hib vaccination in Iranian children by estimating the prevalence of Hib oropharyngeal colonization among children in Tehran. Cultures were prepared from oropharyngeal swabs of 1000 children in 25 day-care centres in Tehran from October 2005 to March 2006. The prevalence of Hib carriers was 7.6%, similar to other developing countries prior to inoculation with the conjugate Hib vaccine. We recommend Hib vaccination be included in the Iranian national programme of immunization.