This review aims to summarize the current literature on the effects of direct, clinical observation of residents in emergency departments (EDs) on learners, patients, and departmental functioning. A systematic literature search was conducted in Medline and ERIC, covering the years 1980-2009. Keywords were used to identify postgraduate medical staff working in the ED; direct observation of these trainees by supervising staff; and reports of outcomes relating to Kirkpatrick's levels of reaction, learning, behavior, and institutional change. From an initial 11,433 abstracts and titles, 193 full-text articles were retrieved for further study. Application of inclusion and exclusion criteria yielded seven that were relevant to the topic. These studies comprised a range of methods-descriptive, qualitative evaluation, cohort studies, and a cross-sectional survey. Learner reaction was very enthusiastic. Positive changes in behavior due to feedback provided during direct observation were suggested by two studies. A single study evaluated trainee's perceptions on patient outcomes and noted that thorough assessments and improved management decisions may be at the expense of slower throughput of patients and diversion of senior staff from direct patient care. Three studies noted the resource-intensive nature of direct observation. Direct observation of clinical practice may be useful in ED education; however, further research is required to evaluate its effects.