Ultrasonography (US) is routinely used as a diagnostic approach in the surgical acute abdomen, even though its major limitation is the demonstration of the hollow viscus. In the present paper, the results obtained with US in 12 cases of gastric or duodenal perforations are reported. The diagnosis, of gastroduodenal perforation was correctly made in 58% of cases by means of US; in 91.7% of cases, at least one US finding correlable with gastroduodenal perforation was observed. Even though US exhibits poorer diagnostic sensitivity than conventional radiology, it can be considered a valuable diagnostic tool in the early diagnosis of gastroduodenal perforation especially when radiographic findings are negative.