Certification helps ensure quality of practice and currency of nursing knowledge. We designed certification review courses and evaluated their impact on satisfaction, quality of care, adverse drug events (ADEs), and RN vacancies. Certification correlated with improved patient and nurse satisfaction, quality of care, and increased nurse rates of reporting ADEs, although the ADE total rates are consistent. Certification inversely correlated with nurse vacancies. Certification has helped to enhance nurses' knowledge, productivity, quality of care, and patient and nurse satisfaction, and has decreased RN vacancies.