Effusive-constrictive pericarditis is typically caused by tuberculosis or other severe inflammatory conditions that affect the pericardium. We report a case of effusive-constrictive pericarditis consequent to a motor vehicle accident. A 32-year-old man with gastroesophageal reflux disease presented with severe sub-sternal chest pain of a month’s duration and dyspnea on exertion for one week. Echo-cardiograms revealed a moderate pericardial effusion, and the diagnosis was subacute effusive-constrictive pericarditis. After thorough tests revealed nothing definitive, we learned that the patient had been in a motor vehicle accident weeks before symptom onset, which made blunt trauma the most likely cause of pericardial injury and effusion. Medical management resolved the effusion and improved his symptoms. To our knowledge, this is the first report of effusion from posttraumatic constrictive pericarditis associated with a motor vehicle accident. We encourage providers to consider recent trauma as a possible cause of otherwise idiopathic pericarditis.