BackgroundTo address the huge human resources for health gap in Zambia, the Ministry of Health launched the National Community Health Assistant Strategy in 2010. The strategy aims to integrate community-based health workers into the health system by creating a new group of workers, called community health assistants (CHAs). However, literature suggests that the integration process of national community-based health worker programmes into health systems has not been optimal. Conceptually informed by the diffusion of innovations theory, this paper qualitatively aimed to explore the factors that shaped the acceptability and adoption of CHAs into the health system at district level in Zambia during the pilot phase.MethodsData gathered through review of documents, 6 focus group discussions with community leaders, and 12 key informant interviews with CHA trainers, supervisors and members of the District Health Management Team were analysed using thematic analysis.ResultsThe perceived relative advantage of CHAs over existing community-based health workers in terms of their quality of training and scope of responsibilities, and the perceived compatibility of CHAs with existing groups of health workers and community healthcare expectations positively facilitated the integration process. However, limited integration of CHAs in the district health governance system hindered effective programme trialability, simplicity and observability at district level. Specific challenges at this level included a limited information flow and sense of programme ownership, and insufficient documentation of outcomes. The district also had difficulties in responding to emergent challenges such as delayed or non-payment of CHA incentives, as well as inadequate supervision and involvement of CHAs in the health posts where they are supposed to be working. Furthermore, failure of the health system to secure regular drug supplies affected health service delivery and acceptability of CHA services at community level.ConclusionThe study has demonstrated that implementation of policy guidelines for integrating community-based health workers in the health system may not automatically guarantee successful integration at the local or district level, at least at the start of the process. The study reiterates the need for fully integrating such innovations into the district health governance system if they are to be effective.