Church-based health promotion has increasingly gained attention in strategies to address health disparities. In Australia, we have limited understanding of the role of local churches in health promotion and without this, how they might be involved in meaningful partnerships to tackle public health challenges. The objective of this qualitative study was to explore how churches are involved in health promotion in the state of Victoria. The research involved in-depth interviews with ministers from 30 churches in urban and rural Victoria, and case studies with 10 of these churches to enable further exploration. These case studies, conducted in 2010, included interviews with church staff, focus groups with volunteers, participant observation and document analysis. Analysis was iterative, utilising open, axial and thematic coding. Three different expressions of church - traditional, new modern and emerging - were identified and found to differentiate the levels and types of health promotion activity. Case studies illustrate the different expressions of how church mission influences health promotion activity. The traditional churches were involved particularly in disease screening and health education activities with their own, predominantly older congregation members. The new modern churches tended to have the material and human resources to be harnessed in health promotion activities involving congregation members and others. Emerging churches, in contrast, engaged in broad health-promoting activities, including disease prevention, lifestyle activities and socio-ecological approaches at a community level. These research findings highlight the opportunities and challenges of engaging with local churches in health promotion efforts and public health programmes to address health inequities.