OBJECTIVES:  Clinical risk stratification of localized prostate cancer (PCa) guides treatment decisions. However, residual uncertainty and inaccurate classification could yield over- or under-treatment of patients considered for interventional treatment or active surveillance. The cell cycle progression (CCP) test, a genomic assay that estimates PCa aggressiveness, could improve accuracy of risk assessment and treatment choice for low- or intermediate-risk patients. This study estimated the five-year budget impact of CCP from an Ontario public payer perspective. METHODS:  A budget impact analysis was conducted by comparing costs between a reference scenario without CCP and a new scenario with CCP. Since no studies have shown CCP’s effect on clinical outcomes, we assumed that CCP would only change the distribution of initial treatments, not progression or survival. Each year an estimated 6,196 men are newly diagnosed with low- or intermediate-risk PCa. Treatment patterns for these groups of patients were obtained from the literature, and the expected uptake of CCP was estimated using expert opinion. The effect of CCP on treatment decisions was based on two clinical utility studies. RESULTS:  We estimated the costs associated with the CCP test itself to be $47.9 million, the costs associated with additional physician visits required to interpret the test result to be $0.7 million, and the savings due to treatment change (increased use of active surveillance and decreased use of interventional treatment) to be −$7.3 million. As a result, publicly funding the CCP test would result in a net budget impact of $41.3 million in the first five years. Results were most sensitive to assumptions regarding the uptake and the extent that CCP altered current treatment. CONCLUSIONS: Publicly funding the CCP test would result in a large incremental cost to the provincial budget.