Three hundred patients who had sustained blunt abdominal injury were evaluated with computed tomography (CT). The images showed areas of hemorrhage by varying attenuation coefficients (average, 45 Hounsfield units; exceeding 30 Hounsfield units in all cases except in those patients with bleeding more than 48 hours old). Small hematomas tended to accumulate near the site of origin while free intraperitoneal bleeding most frequently accumulated in the Morison pouch, paracolic gutters, and pelvis. CT estimates of the extent of hemoperitoneum (small, moderate, or large) correlated well with clinical assessments and surgical findings. Only one false-negative and two false-positive CT interpretations occurred, and each was potentially avoidable in retrospect. CT is sensitive and specific for the diagnosis of hemoperitoneum and can estimate the extent and probable source of bleeding. This information may obviate the need for a peritoneal lavage and laparotomy in many instances.