PURPOSE: Residents are being asked to participate in quality improvement (QI) initiatives in hospitals and clinics with increasing frequency; however, the effectiveness of improving patient care through residents' participation in QI initiatives is unknown. METHOD: A thorough, systematic review of the English-language medical literature published between 1987 and October 2008 was performed to identify clinical QI initiatives in which there was active engagement of residents. Multiple search strategies were employed using PubMed, EMBASE, CINAHL, and ERIC. Articles were excluded in which residents played a passive or peripheral role in the QI initiative. RESULTS: Twenty-eight articles were identified that documented residents' active leadership, development, or participation in a clinical QI initiative, such as curriculum change, clinical guideline implementation, or involvement with a clinical QI team. The role and participation of residents varied widely. Measures of patient health are described as outcomes in the QI initiatives of 5 of the 28 articles. Twenty-three articles described process improvements in patient care or residents' education as the outcome measure. CONCLUSION: There are few articles that describe the clinical or educational effectiveness of residents' participation in QI efforts; the authors describe barriers that may be partly responsible. They conclude that there is a great need for additional research on the effectiveness of residents' participation in QI initiatives, particularly as they affect patient health outcomes.