OBJECTIVES A 3-round hepatitis-B immunization campaign covering 1989-born adolescents was implemented in 2007 in Iran. This study was conducted for cost estimation and analysis of this campaign. METHODS This study was conducted applying health system perspective. The cost variables considered were recurrent costs, personnel costs, publicity costs, transportation costs and overhead costs. As the campaign was implemented using health system facilities, there is no marginal costs for capital items such as building and refrigerator. We provided the required data to estimate recurrent costs, national-level supervision and publicity from existing data and interview with experts. To estimate costs of vaccine administration, provincial supervision and outreach, we provided data from some of the provinces, then expanded the results to the country. We used WHO recommended proportions to estimate transportation and overhead costs. We used administrative data to estimate vaccination coverage. RESULTS At the end of the third round, 70.0% of target population received full doses, 74.5% received at least 2 doses and 78.3% received at least 1 dose of vaccine. Total cost of the campaign was estimated as $8.991 million including 24% for recurrent, 42% for personnel, 31% for transportation, 0.1% for publicity and 3% for overhead. Total cost was estimated as $2.3 per-dose-administered. Sensitivity analysis indicated that increasing campaign coverage upto >90% and using under 20 years old vaccine dosage will decrease the cost to $1.9 per-dose-administered. Decreasing campaign coverage and using above 20 years old vaccine dosage will increase the cost to $2.5. Considering vaccine immunogenicity based on Iranian studies, the cost was estimated $7.1-7.2 per-person-seroprotected. CONCLUSIONS The costs in this campaign are much lower than what in similar programs in developed countries. Acceptable campaign coverage and lower health service cost in Iran can be responsible. More attention is needed to publicity costs in further campaigns.