Chronic intestinal pseudo-obstruction(CIPO) is a rare disease due to a severe gastrointestinal motility disorder which may mimic,on both clinical and radiological grounds,mechanical obstruction.We report a case of a 26-year-old woman who presented to our institution for plain abdominal radiography for referred long-lasting constipation with recurrent episodes of abdominal pain and distension.At X-ray,performed both in the upright and supine position,an isolated air-fluid level was depicted in the left flank,together with a number of radiological signs suggestive of pneumoperitoneum.First,subphrenic radiolucency could be observed in the upright film.Second,the intestinal wall of some jejunal loops appeared to be outlined in the right flank.Third,the inferior cardiac border was clearly depicted in the upright film.The patient however had no evidence ofperitoneal signs but only hypoactive bowel movements.Unenhanced multi-detector computed tomography(MDCT) of the abdomen and pelvis was therefore performed.MDCT revealed abnormal air-driven distension of the small and large bowel,without evidence of extraluminal air.All radiological signs of pneumoperitoneum turned out to be false-positive results.The patient was submitted to pan-colonoscopy and to anorectal manometry to rule out Hirshprung’s disease,and was finally discharged with a diagnosis of CIPO. Chronic intestinal pseudo-obstruction (CIPO) is a rare disease due to a severe gastrointestinal motility disorder which may mimic, on both clinical and radiological grounds, mechanical obstruction. We report a case of a 26-year-old woman who presented to our institution for plain abdominal radiography for referred long-lasting constipation with recurrent episodes of abdominal pain and distension. At X-ray, performed both in the upright and supine position, an isolated air-fluid level was depicted in the left flank, together with a number of radiological signs suggestive of pneumoperitoneum. First, subphrenic radiolucency could be observed in the upright film. Second, the intestinal wall of some jejunal loops Was to be outlined in the right flank.Third, the inferior cardiac border was clearly depicted in the upright film . The patient had had no evidence of peritoneal signs but only hypoactive bowel movements. Unenhanced multi-detector computed tomography (MDCT) of the abdomen and pelvis was the refore performed. MDCT revealed abnormal air-driven distension of the small and large bowel, without evidence of extraluminal air. All radiological signs of pneumoperitoneum turned out to be false-positive results the patient was submitted to pan-colonoscopy and to anorectal manometry to rule out Hirshprung’s disease, and was finally discharged with a diagnosis of CIPO.