Diaphragmatic eventration is a rare disease, congenital or acquired, high or elevated position of one leaf of the diaphragm muscle, as a result of paralysis, aplasia or atrophy of varying degree of the muscle fibers of the affected side but with no break in the continuity of the muscle. We experienced 3 cases of the diaphragmetic eventration at the department of thoracic surgery, C.A.F.G.H., from 1980 to 1982, which were treated successfully. Among three cases, one case combinded with hamartoma of the ipsilateral lung. Specific complications were not noticed after surgical repair of diaphramatic eventration with good result.