Anastomotic leakage is a major postoperative complication. While cell sheet technology has been gaining popularity in the clinical field, the utility of cell sheets for containing contaminated enteral perforation remains unclear. We established a new gastric perforation rat model and evaluated the efficacy of the myoblast cell sheet to prevent leakage. To establish a suitable rat model, perforations of various sizes were made in the stomach. We then pasted the sheet onto the perforated stomach in our new model. After the operation, the rats were sacrificed and analyzed macroscopically and histologically. Serum levels of C-related protein and hyaluronic acid in the peritoneal cavity washing lavage were also evaluated. An incision 5 mm in length was found to be the most suitable for evaluation of the cell sheet performance. In the rats where the cell sheet had been pasted onto the perforation site, we noted less adhesion in the abdominal cavity and a significant reduction in the hyaluronic acid levels in the peritoneal cavity washing lavage. We evaluated the efficacy of cell sheets for preventing leakage of enteral contents in a gastric perforation rat model. Myoblast cell sheets were able to markedly reduce the degree of both intra-abdominal adhesion and inflammation.