Objectives: This study investigates whether instructional methods used by excellent emergency medicine residency teachers change with changing conditions of learner level of training, patient acuity and department census. Methods: Four excellent, purposively selected, emergency medicine teachers consented to participate in this non-participant observational study. Teachers were observed for 32 hours in the emergency department, using a structured observation form focused on: teaching methods used, context learner level of training, emergency department patient census and patients' illness severity. Data was analyzed qualitatively using constant comparative analysis. Results: Fifteen (15) categories of teaching methods were observed. The 4 most frequently observed methods were: Questioning (used in 47of teaching encounters), Advice Giving (33, Limited Teaching Points (31 and Patient Updates (22. Patient Updates were more often used with senior residents. Multiple methods were used in most encounters. Teaching methods did not vary significantly with increased emergency department volume, but faculty and residents relied more heavily on a single method of teaching per encounter as patient acuity increased to Triage levels One and Two. Conclusions: Excellent emergency medicine teachers teaching methods were classified into 15 categories. They typically rely heavily on four methods, adapting to resident training level and patient illness severity, rather than patient volume. The observed teaching methods provide teachers who have high clinical productivity expectations and/or demanding emergency care settings with an enriched repertoire of teaching strategies.