['We hypothesised that in blunt trauma patients with haemodynamic instability and haemoperitoneum on hospital admission, the haemorrhagic source may not be confined to the peritoneum. The purpose of this study was to describe the incidence and location of bleeding source in this population.', 'The charts of trauma patients admitted consecutively between January 2005 and January 2010 to our level I Regional Trauma Centre were reviewed retrospectively. All hypotensive patients presenting a haemoperitoneum on admission were included. Hypotension was defined by a systolic blood pressure ≤ 90 mmHg. The haemoperitoneum was quantified on CT images or from operative reports as moderate (Federle score<3 or between 200 and 500 ml) or large (Federle score ≥ 3 or >500 ml). Active bleeding (AB) was defined as injury requiring a surgical or radiologic haemostatic procedure, regardless of origin (peritoneal (PAB) or extraperitoneal (EPAB)).', 'Of 1079 patients admitted for severe trauma, 110 patients met the inclusion criteria. Seventy-eight (71%) were male, mean age 35.3 (SD 19) years and mean ISS 36.5 (SD 20.5). Among the 91 patients who had AB, 37 patients (41%) had PAB, 34 (37%) had EPAB and 20 had both (22%). Forty-eight (53%) of them had moderate haemoperitoneum and 43 (47%) had large haemoperitoneum. A large haemoperitoneum had positive predictive value for PAB of 88% (95% CI 75-95%) and negative predictive value of 65% (95% CI 49-79%). The corresponding values in the subgroup of patients with EPAB were 65% (95% CI 38-86%) and 76% (95% CI 59-88%).'] Does a haemoperitoneum indicate active bleeding in the peritoneum in 50 % of hypotensive blunt trauma patients : a study of 110 severe trauma patients?