A 28-year-old man with a history of inflammatory bowel disease (IBD) developed sudden-onset chest pain and dyspnea 9 days after esophagogastroduodenoscopy and colonoscopy. A chest radiograph demonstrated pneumomediastinum tracking along the left heart border. The spontaneous pneumomediastinum was presumed to be a complication of his severe colitis. The severity of our patient's symptoms ultimately necessitated a subtotal colectomy, a decision unrelated to the pneumomediastinum. IBD-associated pneumomediastinum can be attributed to retroperitoneal air leakage from severe colitis and usually resolves with conservative management.