An elderly patient with asymptomatic bilateral Bochdalek hernias is reported. The chest roentgenogram showed dome-shaped supradiaphragmatic masses about 6 cm in diameter in the posteromedial regions of both sides of the lungs. Computed tomography showed a discontinuity of the lines of diaphragmatic musculature in the left thorax, and a mass with a homogenous low density area indicative of fatty tissues in the right thorax. The magnetic resonance imaging, coronal and sagittal T1-weighted images revealed interruptions of the diaphragmatic musculature adjacent to the masses and protrusion of retroperitoneal fat into the thoracic cavity. The lesions were therefore diagnosed as bilateral Bochdalek hernias of the diaphragm.