There is a need to understand the costs associated with supporting, implementing, and maintaining the system redesign of small and medium-sized safety-net clinics. The authors aimed to understand the characteristics of clinics that transformed into patient-centered medical homes and the incremental cost for transformation.The sample was 74 clinics in Greater New Orleans that received funds from the Primary Care Access and Stabilization Grant program between 2007 and 2010 to support their transformation. The study period was divided into baseline (September 21, 2007-March 21, 2008), transformation (March 22, 2008-March 21, 2009), and maintenance (March 22, 2009-September 20, 2010) periods, and data were collected at 6-month intervals. Baseline characteristics for the clinics that transformed were compared to those that did not. Fixed-effect models were conducted for cost estimation, controlling for baseline differences, using propensity score weights.Half of the 74 primary care clinics achieved transformation by the end of the study period. The clinics that transformed had higher total cost, more clinic visits, and a larger female patient proportion at baseline. The estimated incremental cost for clinics that underwent transformation was $37.61 per visit per 6 months, and overall it cost $24.86 per visit per 6 months in grant funds to support a clinic's transformation.Larger-sized clinics and those with a higher female proportion were more likely to transform. The Primary Care Access and Stabilization Grant program provided approximately $24.86 per visit over the 2 and 1/2 years. This estimated incremental cost could be used to guide policy recommendations to support primary care transformation in the United States.