One of the main limitations of 18F-fluoro-2-deoxy-glucose positron emission tomography/computed tomography (FDG PET/CT) is false-positive tracer uptake by physiological and inflammatory conditions. Continuing FDG accumulation occurs in tumors, but not in inflammatory lesions, and dual time-point FDG PET can be useful for differentiating benign from malignant conditions. Experience is rather limited, and its application in the assessment of tumors inside peritoneal cavity has been rarely reported. We present 2 cases where dual time-point FDG PET imaging proved essential in differentiating intense physiological tracer uptake from peritoneal deposits in patients with intestinal obstruction.