Omental cake is defined as a pancake-like diffuse thickening of the greater omentum stretching from the greater curvature of the stomach down to the lower abdomen. The causes of omental cake are metastatic ab-dominal tumor mesothelioma and peritonitis. The authors evaluated the sonographic findings of omental cakes in 29 patients with metastatic cancer and 17 patients with bacterial or tuberculous peritonitis. Omental cakes were diffuse (78%) or localized (22%) hyperechoic(78%) or heterogenous echogenic (22%) and irregular or smooth. There was no differential point between malignant tumor and inflammation. The authors stress that a radiologist should be alert to detect an omental cake as a staging work-up in patients with cancer or peritoneal infalmmatory disease.