Maintenance of Certification (MOC) is the most recent stage in the evolution of specialty board certification. Driven by increasing concerns over the quality and safety of medical care, MOC represents a change in the frequency and the nature of the requirements of existing recertification. Under MOC, the every 10-year snapshot of professionalism, participation in continuing medical education, and medical expertise that are part of current recertification will become a more continuous process. MOC adds the assessment of practice performance to these measures and represents a philosophical change as well as a requirement change. The focus of these assessments is for improvement rather than judgment. The extent to which MOC succeeds will reflect surgeons' ability to improve the quality of care through voluntary efforts.