Costing is a major activity to define future service packages, plan payment methods and measure the efficiency of the healthcare system. Maternal, neonatal and child health (MNCH) services are of high importance in Bangladesh for meeting MDGs (4 and 5). Several MNCH programs have been initiated in Bangladesh and for some of them costs of services have been estimated. However, the cost of behavior change communication (BCC), which is considered to be an integral part of MNCH, has not been rigorously estimated in Bangladesh. Manoshi, a MNCH program has been operating in urban slums of all city corporation areas by BRAC since 2007. BCC key messages in Manoshi are delivered through thirteen subchannels within three broader categories of channels. The objective of this current study is to estimate the costs of BCC interventions through 13 sub-channels separately. Pregnant women, their husband and community people in the urban slums of Dhaka city, where Manoshi program is being implemented, has been investigated. The study is conducted during November, 2010 to April, 2011 in urban slums of Dhaka City where Manoshi program is being implemented. Micro-costing approach is utilized for calculating unit cost using primary and secondary sources. Primary data is collected through interview of service-providers and managers, observation of group counseling and mass media events and informal group meeting. Information on magnitude of services provided is taken from secondary sources. The cost of BCC tools per exposed is calculated. BCC cost of FFC counseling is 2.94 BDT for pregnancy identification; 3.02 BDT for pregnancy confirmation; 11.24 BDT for antenatal care; 18.10 BDT for delivery care and 20.83 BDT for post natal care. Cost of group counseling is 22.31 BDT for EDD meeting (women in later-stage pregnancy); 13.74 BDT for Women Support Group meeting; 16.92 BDT for MNCH committee meeting; and 6.62 BDT for spouse forum meeting. Mass media cost is 9.42 BDT for folksong; 26.27 BDT for street drama, 0.40 BDT for TV-broadcasting and 2.61 BDT for billboard. We found that BCC intervention channel, group counseling costs highest per exposed (59.63 BDT or US$ 0.82), followed by face-to-face counseling (56.13 BDT or US$ 0.77) and mass media (38.83 BDT or US$ 0.53). The costs per exposed through 13 BCC sub-channels are found. The cost per exposed vary significantly across BCC intervention channels. Some of the inputs appear as the cost drivers, namely, personnel, BCC materials and refreshment costs. However, the major cost drivers vary across different channels and sub-channels. The cost per exposed can be used for estimating total costs of BCC interventions in ongoing and future projects, planning the cost containment and resource allocation across different BCC sub-channels.