We describe a case of spontaneous gastric rupture in a child of 5 years old. The patient reached us in a serious condition; the anamnesis was negative for traumatic events or gastrointestinal disorders. An abdominal X-ray and CT scan revealed free air and fluid in the abdominal cavity, leading to the diagnosis of gastro-intestinal perforation. Submitted to urgent surgery, a rupture of the posterior wall of the stomach was found that was treated with gastrectomy "à la demande". The surgery follow-up was regular. Morphological and immunohistochemical study showed some muscular abnormalities of the muscular gastric wall.