A randomized controlled study assessed a self-paced, online educational course addressing the complex nursing care of hospitalized patients on basal-bolus insulin. Interactive quizzes and scenarios were used to reinforce learning. Knowledge in the intervention group increased significantly and was retained 3-months postintervention. Nursing professional development educators will find this article useful regarding methods for annual competency evaluation and for increasing staff's knowledge as part of a system approach for safely caring for patients with diabetes.