Over the last 10 years, 26 patients have undergone repair of blunt traumatic diaphragmatic injury. Motor vehicle accidents were the cause in 77 per cent of these cases. The diagnosis was made immediately by chest x-ray in eight of 26 cases, and in ten cases, the diagnosis was made at celiotomy because of other suspected intraabdominal injury. The other eight cases fell into two categories; delayed (diagnosis made within same hospitalization) and late (diagnosis made at subsequent presentation). In many cases in which diaphragmatic injuries were missed or delays in diagnosis occurred, radiologic evidence for possible injury was present on the initial chest x-ray, but the diagnosis was not suspected. Seventy-seven per cent of patients (20 of 26) had associated major injuries (spleen, chest, extremities). The left hemidiaphragm was involved in 19 patients and right diaphragmatic injuries in seven patients. Repair was accomplished in 23 cases transabdominally with a thoracoabdominal extension required in three patients because of severe liver trauma. The three cases in which the diagnosis was delayed had diaphragmatic defects repaired by a transthoracic approach.