BACKGROUND: The cost of behavior change communication (BCC) interventions has not been rigorously studied in Bangladesh. This study was conducted to assess the implementation costs of a BCC intervention in a maternal, neonatal and child health program (Manoshi) run by BRAC, which has been operating in the urban slums of Dhaka since 2007. The study estimates the costs of BCC tools per exposure among the different types of BCC channels: face-to-face, group counseling, and mass media. METHODS: The study was conducted from November 2010 to April 2011 in the Dhaka urban slum area. A micro-costing approach was applied using primary and secondary data sources to estimate the cost of BCC tools. Primary data were collected through interviews with service-providers and managers from the Manoshi program, observations of group counseling, and mass media events. RESULTS: Per exposure, the cost of face-to-face counseling was found to be 3.08 BDT during pregnancy detection, 3.11 BDT during pregnancy confirmation, 12.42 BDT during antenatal care, 18.96 BDT during delivery care and 22.65 BDT during post-natal care. The cost per exposure of group counseling was 22.71 BDT (95 % CI 21.30-24.87) for Expected Date of Delivery (EDD) meetings, 14.25 BDT (95% CI 12.37-16.12) for Women Support Group meetings, 17.83 BDT (95% CI 14.90-20.77) for MNCH committee meetings and 6.62 BDT (95% CI 5.99-7.26) for spouse forum meetings. We found the cost per exposure for mass media interventions was 9.54 BDT (95% CI 7.30-12.53) for folk songs, 26.39 BDT (95% CI 23.26-32.56) for street dramas, 0.39 BDT for TV-broadcasting and 7.87 BDT for billboards. Considering all components reaching the target audience under each broader type of channel, the total cost per exposure was found to be 60.22 BDT (0.82 USD) for face-to-face counseling, 61.40 BDT (0.82 USD) for group counseling and 44.19 BDT (0.61 USD) for mass media. CONCLUSIONS: The total cost for group counseling was the highest per exposure, followed by face-to-face counseling and mass media. The cost per exposure varied substantially across BCC channels due to differences in cost drivers such as personnel, materials and refreshments. The cost per exposure can be valuable for planning and resource allocation related to the implementation of BCC interventions in low resource settings.