BACKGROUND: Chronic pain, sensory disturbances, and lymphedema are frequent after breast cancer, leading to arm dysfunction. There is a need for objective performance-based clinical exercise tests for the upper extremity in patients with breast cancer. OBJECTIVE: The aim of this study was to evaluate the validity and reliability of the 6-minute pegboard and ring test (6PBRT) in breast cancer survivors. METHODS: Forty-eight women with breast cancer (mean age = 55.40 ± 10.40 years) were included. All patients performed 6PBRT on the first day and one week later to investigate the test-retest reliability of the 6PBRT, and intraclass correlation coefficients (ICC) were calculated. The peak workload (W RESULTS: The 6PBRT showed good test - retest reliability with an ICC CONCLUSION: The 6PBRT has good test-retest reliability and is a valid test in individuals with breast cancer. These findings suggest that 6PBRT is a practical, useful, valid and reliable assessment tool for determining functional arm exercise capacity in patients with breast cancer.