Background: In a primary analysis of the STAMPEDE protocol, the addition of Abiraterone acetate to androgen deprivation therapy (ADT) in men with castration sensitive, high-risk, non-metastatic prostate cancer was associated with significantly higher rates of metastasis-free survival compared with ADT alone. However, the cost-effectiveness of Abiraterone in this population remains unaddressed. Methods: A decision model based on partitioned survival simulations estimated costs and quality-adjusted life years (QALY), and incremental cost-effectiveness ratios (ICERs) associated with ADT with or without Abiraterone. This analysis was performed from a United States healthcare sector perspective. We estimated drug acquisition costs using the Federal Supply Schedule. Given current heterogeneity in prescription drug coverage, we used both brand-name and generic drug prices. The willingness-to-pay (WTP) threshold was $100,000 per QALY. Analyses were performed over the published STAMPEDE trial with median follow-up duration of 72 months. Model input parameters were based on the STAMPEDE trial data as well as best available and most recent data provided in the published literature. Sensitivity analyses explored uncertainty with regard to the model assumptions. Results: Using brand-name pricing, the addition of Abiraterone to ADT was associated with an increase in net costs by $217,616, and an increase in QALYS by 0.79. Therefore, the ICER associated with brand-name Abiraterone was $277,156 per QALY. Sensitivity analyses revealed that the monthly price of Abiraterone would need to be less than or equal to $2,581 in order to be cost-effective at a WTP threshold of $100,000 per QALY. In contrast, generic Abiraterone was associated with an increase in net costs by $45,325, and a cost-effective ICER of $57,726 per QALY. Conclusions: Abiraterone for high-risk non-metastatic prostate cancer is cost-effective using generic pricing. However, current brand-name pricing is roughly four times the threshold of cost-effectiveness, underscoring the need to increase access to generic drugs in the United States.