BackgroundThe food system has a dynamic influence on disparities in food security and diet-related chronic disease. Community supported agriculture (CSA) programs, in which households receive weekly shares of produce from a local farmer during the growing season, have been examined as a possible food systems-based approach for improving diet and health outcomes. The purpose of this study was to estimate the cost of implementing and participating in a multi-component subsidized community supported agriculture intervention and calculate cost-effectiveness based on diet and food security impacts.MethodsUsing data from the Farm Fresh Foods for Healthy Kids (F3HK) randomized controlled trial in New York, North Carolina, Vermont, and Washington (n = 305; 2016–2018), we estimated programmatic and participant costs and calculated incremental cost-effectiveness ratios (ICERs) for caregivers’ daily fruit and vegetable (FV) intake, skin carotenoids, and household food security from program and societal perspectives.ResultsF3HK cost $2,439 per household annually ($1,884 in implementation-related expenses and $555 in participant-incurred costs). ICERs ranged from $1,507 to $2,439 per cup increase in caregiver’s FV intake (depending on perspective, setting, and inclusion of juice); from $502 to $739 per one thousand unit increase in skin carotenoid score; and from $2,271 to $3,137 per household shifted out of food insecurity.ConclusionsGiven the known public health, healthcare, and economic consequences of insufficient FV intake and living in a food insecure household, the costs incurred to support these positive shifts in individual- and household-level outcomes via a F3HK-like intervention may be deemed by stakeholders as a reasonable investment. This work helps to advance a critical body of literature on the cost-effectiveness of subsidized CSAs and other economic and food system interventions for the sake of evidence-based allocation of public health resources.Trial registration: ClinicalTrials.gov. NCT02770196. Registered 5 April 2016. Retrospectively registered.https://www.clinicaltrials.gov/ct2/show/NCT02770196.