This chapter describes the disability and dysfunction. Over the past two decades, disability and dysfunction have emerged as major concepts in chronic pain experience and assessment. Pain-related disability has widespread impact on adjustment to chronic pain vis-a-vis mood dysregulation, cognitions of burdensomeness, socioeconomic stress related to decreased work attendance and potential job loss, and inability to access external coping resources for pain management. Disability can also be assessed through “objective” measures of lifting capacity, aerobic capacity, gait, and range of motion. Biomechanical or neurologic deficits, especially which result in limb or trunk weakness, spasticity, or deformity, may require specific treatment and adaptation. Physical therapy, orthotics, external bracing, prosthetics, or even intrathecal therapy may be needed to improve functional outcome.