Base deficit (BD) and lactic acid (LA) are accepted markers of hypoperfusion and predictors of outcome in the trauma patient and we aim to assess the value of these markers in the triage of the elderly with "normal" vital signs. Patients older than age 65 who presented between 1997 and 2004 but who did not have isolated head injuries were included. Three patient groups were established: normal, occult hypoperfusion (OH), and shock. Outcome measures included mortality, hospital length of stay, intensive care unit length of stay, and discharge disposition. One hundred six patients were included in the analysis and had similar Injury Severity Scores. Mean systolic blood pressure was similar in the normal and OH groups. Forty-two per cent of patients had abnormal BD or LA in the emergency room indicating OH. These patients were more likely to have a longer intensive care unit length of stay (8.6 days vs. 3 days; P = 0.01) and were also more likely to be discharged to a nursing facility (P = 0.03). The trend was toward increased mortality in the OH group. OH is a common finding in elderly trauma patients. Outcomes in these patients are different and more like those presenting in shock.