An abdominal X-ray is an X-ray examination of the abdominal contents. An abdominal X-ray is often one of the first steps in the investigation of acute abdominal disease. X-rays do not reveal the internal structure of organs, but they do show their outlines.

X-rays can therefore show whether any organ is enlarged and can detect swallowed foreign bodies in the digestive tract. X-rays also show accumulations of fluid and gas: distended loops of bowel containing collections of fluid often indicate the presence of an obstruction; gas outside the intestine indicates intestinal perforation.

Calcium, which is opaque to X-rays, is present in most kidney stones and in some gallstones and aortic aneurysms; these can sometimes be detected on an abdominal X-ray.

Abdominal X-rays may need to be followed by procedures that provide more information, such as ultrasound scanning, barium X-ray examinations (use of a contrast medium to detect disorders of the gastrointestinal tract), laparoscopy (internal examination of the abdomen using a viewing instrument), CT scanning or MRI (techniques that produce cross-sectional or three-dimensional images of body structures).