To summarize the literature regarding the effect of clinical supervision on patient and educational outcomes, especially in light of the recent (2010) Accreditation Council for Graduate Medical Education report that recommends augmented supervision to improve resident education and patient safety.The authors searched the English-language literature from 1966 to 2010 using electronic databases and a hand search. They included studies that described a controlled design, and they have relayed the effects of supervision on patient- and education-related outcomes. Two authors abstracted prescribed data from the reviewed studies. The authors rated the quality of each study using the Medical Education Research Study Quality Instrument.Twenty-four articles across a variety of specialties (i.e., psychiatry, emergency medicine, surgery, anesthesia, and internal medicine) met inclusion criteria. Studies demonstrated that enhanced supervision in already-supervised activities resulted in improved patient- or education-related outcomes. Studies were limited by small sample sizes, nonrandomized designs, and a lack of objective measures of clinical supervision.Enhanced clinical supervision of trainees has been associated with improved patient- and education-related outcomes in published studies. Future work should focus on developing validated measures of the effects of clinical supervision.