Between 1 January 1993 and 1 January 1994, 204 consecutive patients with possible blunt abdominal injury were analysed retrospectively. All patients underwent a standardized diagnostic approach on admission to the emergency room. Abdominal ultrasound (AUS) was performed in all cases. If there was evidence of intra-abdominal injury on physical examination or AUS, without signs of persistent hypovolaemia after initial assessment, contrast-enhanced computed tomographic scanning (CECT) of the abdomen was carried out without exception. Physical examination was equivocal in 13 and 3 per cent, respectively, of patients with 'isolated' abdominal trauma (N = 23) or with fractures of lower ribs 7-12 as a sole diagnosis (N = 30). In multiple injury patients (N = 95) or those with suspected 'isolated' head injury (N = 56), these figures reached 45 and 84 per cent, respectively. AUS (N = 204) revealed intra-abdominal injury in 20 per cent of patients, and CECT (N = 43) resulted in additional information in 49 per cent. Patients with 'isolated' head injury showed 9 per cent abnormalities on abdominal evaluation versus 32 per cent in multiple injury patients. In lower rib fractures (7-12) in multiple injury patients abdominal injury was diagnosed in 67 per cent of the cases. We conclude that: (1) negative findings following reliable physical examination of patients with 'isolated' head injury show very high values (NPV 100 per cent), but reliable physical examination is very infrequent (16 per cent); (2) NPV in lower rib fractures due to low energy impact is very high (100 per cent), with a reliable physical examination in most patients (97 per cent); (3) in patients with isolated abdominal trauma 87 per cent have a reliable physical examination with a moderately high NPV (71 per cent); (4) almost half the multiple injury patients have an unequivocal physical examination (45 per cent), with a high NPV following reliable physical examination for abdominal injury (85 per cent); (5) abdominal ultrasonography should be the first step in the radiological assessment of all patients with possible blunt abdominal injury; (6) in multiply injured patients with fractures of their lower ribs (7-12) due to high energy impact the incidence of abdominal injury is very high and CECT might be indicated even in the case of normal AUS findings.