Aim: The goal of the work was comparing gas ultrasound images below the right diaphragm in two groups: in people with intestinal interposition below the diaphragm and ones with pneumoperitoneum and extracting the traits differentiating these two conditions. Material and methods: Retrospectively, the documentation of 22 patients with intestinal interposition below the diaphragm (group 1) was utilized. Clinical material was used for comparison, previously published, composed of 15 cases of pneumoperitoneum following laparotomy and of 14 cases following that symptom as a result of ulcer perforation – group 2 (in total n = 29). Moreover, the distance in millimeters of the gas surface reflecting ultrasounds from the parietal peritoneum was measured, the smoothness of the surface, parietal peritoneum enhancement at the place of gas adherence, gas continuity below the diaphragm with gas in the intestine located below the liver. Results: Direct adherence of the gas surface to the diaphragm was observed in 100% of the cases of emphysema, but in no cases of intestinal interposition. Yet, in the group of patients with colonic interposition (n = 21) there was always a small gap (2–3 mm) and the gas surface among those patients in 100% of the cases was uneven. Conclusions: In differentiation between pneumoperitoneum and liverdiaphragm interposition of the intestine one should take into account – apart from gas movement below the diaphragm at body position changing – the presence of protrusion and section enhancement of the diaphragmatic peritoneum as well as the distance of the gas from the diaphragm, the smoothness of its surface and the continuity with the intestine below the liver. Interpositions of small diaphragm-liver penetration may subside in erect position.