Objective: In 2013, the American College of Emergency Physicians joined the Choosing Wisely campaign; however, its impact on emergency physician behavior is unknown. We assessed knowledge, attitudes, and self-reported behaviors regarding the Choosing Wisely recommendations. Methods: We performed a cross-sectional survey of emergency physicians at a national meeting. We approached 819 physicians; 765 (93.4%) completed the survey. Results: As a result of the Choosing Wisely campaign, most respondents (64.5%) felt more comfortable discussing low-value services with patients, 54.5% reported reducing utilization, and 52.5% were aware of local efforts to promote the campaign. A majority (62.97%) of respondents were able to identify at least four of five recommendations. The most prevalent low-value practices were computed tomography (CT) brain for minor head injury (29.9%) and antibiotics for acute sinusitis (26.9%). Few respondents reported performing lumbar radiograph for nontraumatic low back pain (7.8%) and Foley catheter for patients who can void (5.6%). Respondents reported patient/family expectations as the most important reason for ordering antibiotics for sinusitis (68%) and imaging for low back pain (56.8%). However, concern for serious diagnosis was the most important reason for performing CT chest for patients with normal D-dimer (49.7%) and CT abdomen for recurrent uncomplicated renal colic (42.5%). A minority (3.8% to 26.7%) of respondents identified malpractice risk as the primary reason for performing low-value services. Conclusions: Despite familiarity with Choosing Wisely, many emergency physicians report performing low-value services. Primary reasons for low-value services differ: antibiotic prescribing was driven by patient/family expectations, while concern for serious diagnosis influenced advanced diagnostic imaging. Greater efforts are needed to promote effective dissemination and implementation; such efforts may be targeted based on differing reasons for low-value services.