Background: Green building systems have proliferated but health outcomes and associated costs and benefits remain poorly understood. Objective: To compare health before and after families moved into new green healthy housing with a control group in traditionally repaired housing. Design and Setting: Mixed methods study in 3 Chicago housing developments. Participants: Public housing and low-income subsidized households (n = 325 apartments with 803 individuals). Main Outcome Measures: Self-reported health status, visual assessment of housing condition, indoor air sampling, and Medicaid expenditure and diagnostic data. Medicaid expenditures and International Classification of Diseases, Ninth Revision codes were modeled using a generalized linear model with. distribution and log-link. Results: Housing conditions and self-reported physical and mental health improved significantly in the green healthy housing study group compared with both the control group and the dilapidated public housing from which the residents moved, as did hay fever, headaches, sinusitis, angina, and respiratory allergy. Asthma severity measured by self-reported lost school/work days, disturbed sleep, and symptoms improved significantly, as did sadness, nervousness, restlessness, and child behavior. Medicaid data in this exploratory study were inconclusive and inconsistent with self-reported health outcomes and visual assessment data on housing quality but hold promise for future investigation. Possible sources of bias in the Medicaid data include older age in the study group, changes in Medicaid eligibility over time, controlling for Medicaid costs in an urban area, and the increased stress associated with moving, even if the move is into better housing. Conclusion: The mixed method approach employed here describes the complex relationships among self-reported health, housing conditions, environmental measures, and clinical data. Housing conditions and self-reported physical and mental health improved in green healthy housing. Health care cost savings in Medicaid due to improved housing could not be quantified here but hold promise for future investigations with larger cohorts over a longer follow-up period.