A retrospective clinical study was performed to evaluate the hernias encountered in the anterior part of the diaphragm. Twenty patients (14 males, 6 females; aged 7 days-7 years) with hernias located in the anterior part of the diaphragm who were treated surgically formed the study group. The exact locations, contents and additional malformations were evaluated. The locations were parasternal in 14 and retrosternal in six. Parasternal locations were the right side in 11, left side in two and bilateral in one patient. Three patients had trisomy 21 syndrome. A sac was presented in all cases and included the colon in 12 patients. A patient with retrosternal location also had trisomy 21 syndrome. The patients with retrosternal hernias also presented with sacs, and the colon was the most commonly included viscus. In the presented series, no intrapericardial herniations or anteromedial defects were encountered. Comparison of previously reported patients and the present series suggests that the anterior part of the diaphragm hosts various hernias of congenital origin in its different locations. According to the exact location and the presence or absence of sacs, four different types of hernias occur in this area: retrosternal hernias with a sac, intrapericardial herniation, and parasternal and anteromedial hernias with either unilateral or bilateral involvements. Since four different hernias were distinguished, the term Morgagni hernia does not include or define all the hernias of the anterior part of the diaphragm. We believe they should, therefore be designated according to the location and presence or absence of a sac.