Acute esophageal necrosis (AEN), also known as "Black esophagus", is a rare condition that typically presents as upper gastrointestinal hemorrhage. A retrospective chart analysis was conducted at two tertiary care hospitals over a three-year period (2005-2007) using a computerized inpatient database. Out of 9,179 upper endoscopies performed, five patients (0.05% prevalence) were found to have black esophagus. Their mean age was 44 years and the most common presentation was upper gastrointestinal bleeding. All five patients had comorbid conditions, most commonly coronary artery disease, diabetes mellitus, and renal insufficiency. Two patients died, but the cause of death was not related to AEN in either. In conclusion, AEN is usually seen in critically ill elderly patients with multiple comorbid conditions, particularly vascular disease, diabetes mellitus and azotemia.