Background MANOSHI, an integrated community-based package of essential Maternal, Neonatal and Child Health (MNCH) services is being implemented by BRAC in the urban slums of Bangladesh since 2007. The objective of the formative research done during the inception phase was to understand the context and existing resources available in the slums, to reduce uncertainty about anticipated effects, and develop and refine the intervention components. Methods Data were collected during Jan-Sept 2007 in one of the earliest sites of programme intervention in the Dhaka metropolitan area. A conceptual framework guided data collection at different stages. Besides exploring slum characteristics, studies were done to map existing MNCH service providing facilities and providers, explore existing MNCH-related practices, and make an inventory of community networks/groups with a stake in MNCH service provision. Also, initial perception and expectations regarding the community delivery centres launched by the programme was explored. Transect walk, observation, pile sorting, informal and focus group discussions, in-depth interviews, case studies, network analysis and small quantitative surveys were done to collect data. Results Findings reveal that though there are various MNCH services and providers available in the slums, their capacity to provide rational and quality services is questionable. Community has superficial knowledge of MNCH care and services, but this is inadequate to facilitate the optimal survival of mothers and neonates. Due to economic hardships, the slum community mainly relies on cheap informal sector for health care. Cultural beliefs and practices also reinforce this behaviour including home delivery without skilled assistance. Men and women differed in their perception of pregnancy and delivery: men were more concerned with expenses while women expressed fear of the whole process, including delivering at hospitals. People expected 'one-stop' MNCH services from the community delivery centres by skilled personnel. Social support network for health was poor compared to other networks. Referral linkages to higher facilities were inadequate, fragmentary, and disorganised. Conclusions Findings from formative research reduced contextual uncertainty about existing MNCH resources and care in the slum. It informed MANOSHI to build up an intervention which is relevant and responsive to the felt needs of the slum population.