IMPORTANCE: Value-driven payment system reform is a potential tool for aligning economic incentives with the improvement of quality and efficiency of health care and containment of cost. Such a payment system has not been researched satisfactorily in full-cycle cancer care. OBJECTIVE: To examine the association of outcomes and medical expenditures with a bundled-payment pay-for-performance program for breast cancer in Taiwan compared with a fee-for-service (FFS) program. DESIGN, SETTING, AND PARTICIPANTS: Data were obtained from the Taiwan Cancer Database, National Health Insurance Claims Data, the National Death Registry, and the bundled-payment enrollment file. Women with newly diagnosed breast cancer and a documented first cancer treatment from January 1, 2004, to December 31, 2008, were selected from the Taiwan Cancer Database and followed up for 5 years, with the last follow-up data available on December 31, 2013. Patients in the bundled-payment program were matched at a ratio of 1:3 with control individuals in an FFS program using a propensity score method. The final sample of 17 940 patients included 4485 (25%) in the bundled-payment group and 13 455 (75%) in the FFS group. MAIN OUTCOMES AND MEASURES: Rates of adherence to quality indicators, survival rates, and medical payments (excluding bonuses paid in the bundled-payment group). The Kaplan-Meier method was used to calculate 5-year overall and event-free survival rates by cancer stage, and the Cox proportional hazards regression model was used to examine the effect of the bundled-payment program on overall and event-free survival. Sensitivity analysis for bonus payments in the bundled-payment group was also performed. RESULTS: The study population included 17 940 women (mean [SD] age, 52.2 [10.3] years). In the bundled-payment group, 1473 of 4215 patients (34.9%) with applicable quality indicators had full (100%) adherence to quality indicators compared with 3438 of 12 506 patients (27.5%) with applicable quality indicators in the FFS group (P < .001). The 5-year event-free survival rates for patients with stages 0 to III breast cancer were 84.48% for the bundled-payment group and 80.88% for the FFS group (P < .01). Although the 5-year medical payments of the bundled-payment group remained stable, the cumulative medical payments for the FFS group steadily increased from $16 000 to $19 230 and exceeded pay-for-performance bundled payments starting in 2008. CONCLUSIONS AND RELEVANCE: In Taiwan, compared with the regular FFS program, bundled payment may lead to better adherence to quality indicators, better outcomes, and more effective cost-control over time.