A case of right-sided diaphragmatic rupture due to blunt trauma is reported. The diagnosis was confirmed by sonography and diagnostic pneumoperitoneum. Ultrasonography was of great value by showing a discontinuous, 'flapping' ruptured diaphragm. Computed tomography was of no value. It was concluded that when right-sided diaphragmatic rupture is suggested sonographic examination should be performed. If the sonographic examination is non-diagnostic, a pneumoperitoneum should follow.