Background: Recent years have seen progress in transabdominal ultrasonography (TUS) of the stomach and intestine as a result of more exact evaluation of the wall stratification of these organs and the thickness and echogenicity of the layers, some of these caused by interface echo. These echoes are produced at a tissue interface, where the acoustic impedance changes between two tissues. An interface echo layer is different from a histological layer. With careful TUS of the stomach and intestines it is possible to diagnose lesions of these organs despite silent clinical symptoms. Material/Methods: The material included 340 patients in whom lesions were detected by means of TUS: 88 cases of stomach lesions, 15 cases of small intestine lesions, 215 cases of large intestine lesions, and 22 cases of appendicitis. Endoscopic and histopathological examinations as well as 42 reliable radiological examinations of these patients were performed. The results of these examinations were subjected to statistical assessment. Results: Of the 88 cases of stomach lesions detected by ultrasonography, 68 were confirmed by gastroscopy and 20 by reliable radiological double-contrast examination. In this group, 72 patients without clinical data and 16 patients with clinical symptoms of stomach pathology were examined. From these data it is evident that correct diagnoses were established using ultrasonography in 84% of the examined patients, whereas 16% of the results were false positive. Of the 16 cases of clinically suspected stomach lesions, the proportion of correct diagnoses established by means of ultrasonography constituted the greater part and amounted to 93% of the examined patients (15 patients). This fact perhaps demonstrates that the examining radiologist, who was made "sensitive" by the clinician, searched more precisely for lesions and, above all, that the lesions were more advanced, causing clinical signs and symptoms and better visibility of these lesions in the ultrasonograph. Of the 15 cases of small intestine lesions detected by ultrasonography, 12 (80%) were confirmed by double-contrast radiological examinations, whereas 3 cases showed no lesions, i.e. 20% of the results of the small intestine were carried out on referral because of clinically suspected small intestine lesions. Of this group was only 1 case of an unconfirmed ultrasonography diagnosis (40% false-positive results). Of the 215 cases of large intestine lesions detected by ultrasonography, 128 were confirmed by endoscopic examination and 22 by reliable radiological examination, whereas 57 cases of lesions demonstrated with ultrasonography were not confirmed, which makes 27% false-positive results. Forty large intestine ultrasonographs were made on referral because of clinically suspected lesions in the large intestine. In this group the proportion of false-positive results was smaller (10%) than that of examinations performed in patients without clinical signs/symptoms of intestine pathology (30%). Conclusions: TUS examinations of the stomach and small and large intestine have a high diagnostic value, and each abdominal cavity ultrasonography should include such examination, also in cases where there are no clinical signs and symptoms of alimentary tract pathology. In this study we could not determine the proportion of lesions that were not detected with TUS, i.e. the false-negative proportion.