Anchoring bias is the tendency to focus on an initial diagnosis despite later evidence to the contrary. This study measured physicians’ potential anchoring bias regarding patients with congestive heart failure (CHF) with shortness of breath presenting to the emergency department. When the patient’s initial triage note included CHF, physicians were less likely and/or slower to test for pulmonary embolism (PE) than when the triage note did not mention CHF. This suggests physicians may have been subject to anchoring bias.