ObjectiveAdvanced life support (ALS) guidelines are widely adopted for healthcare provider training with recommendations for retraining every two years or longer. This systematic review studies the retention of adult ALS knowledge and skills following completion of an ALS course in healthcare providers. MethodsWe retrieved original articles using Medline, CINAHL, Cochrane Library, and PubMed, and reviewed reference citations to identify additional studies. We extracted data from included articles using a structured approach and organized outcomes by evaluation method, and knowledge and skills retention. ResultsAmong 336 articles retrieved, 11 papers were included. Most studies used multiple-choice questionnaires to evaluate knowledge retention and cardiac arrest simulation or other skills tests to evaluate skills retention. All studies reported variable rates of knowledge or skills deterioration over time, from 6 weeks to 2 years after training. Two studies noted retention of knowledge at 18 months and up to 2 years, and one reported skills retention at 3 months. Clinical experience, either prior to or after the courses, has a positive impact on retention of knowledge and skills. ConclusionThere is a lack of large well-designed studies examining the retention of adult ALS knowledge and skills in healthcare providers. The available evidence suggests that ALS knowledge and skills decay by 6 months to 1 year after training and that skills decay faster than knowledge. Additional studies are needed to help provide evidence-based recommendations for assessment of current knowledge and skills and need for refresher training to maximize maintenance of ALS competency.