Haemophilus influenzae type b (Hib) disease is estimated to cause 3 million cases of meningitis and severe pneumonia and approximately 386,000 deaths worldwide per year in children aged <5 years. Safe and effective Hib conjugate vaccines have been widely used in industrialized countries for nearly 20 years. However, primarily because of financial constraints and lack of awareness among both public health officials and the public regarding Hib disease burden and benefits of the vaccine, use of these vaccines has been low in developing countries, where most Hib disease and deaths occur. In 2000, the GAVI Alliance (formerly known as the Global Alliance for Vaccines and Immunizations) began providing financial support for Hib vaccine in 72 countries that had a gross national income of < or =$1,000 (USD) per capita. Despite this support, before 2005, adoption of Hib vaccine by these countries remained low. In response, in June 2005, the GAVI Alliance established the Hib Initiative to accelerate evidence-informed decision making regarding use of Hib vaccine in GAVI-eligible countries. During 2004-2007, the number of GAVI-eligible countries using Hib vaccine or approved to use the vaccine increased from 13 (18%) to 47 (65%).