This paper examines inequalities in the use of, and access to, vaccination service in Bangladesh by analyzing national and small area-based datasets. The analysis showed that female children had a lower immunization coverage than male children--the difference persists for all antigens and widens against girls for higher doses. The immunization coverage was higher for children whose mothers were more educated. Children whose fathers had a higher-status occupation (salaried employment) were two-and-a-half times more likely to be immunized than children whose fathers held a lower-status job, e.g. day-labourer. The coverage for the poorest quintile was 70% of the well-to-do. Children residing in urban areas were more likely to be fully immunized than their rural counterparts (70% vs 59% for children aged 12-23 months). Within urban areas, the situation in slums was worse. Large differences existed among the various administrative regions of the country. Ethnic minorities in the Chittagong Hill Tracts had a lower immunization coverage than the Bangalees. In Sylhet, children of non-local workers in Bangladesh-owned tea estates had a lower coverage than their counterparts in foreign-owned tea estates. The study identifies children of various disadvantaged groups as having a lower coverage. Managers of immunization programmes must realize that only through removal of such disparities among groups will overall coverage be increased. Affirmative actions in targeting could be effective in reaching such groups.