A pattern of multiple organ dysfunction syndrome (MODS) and risk factors following blunt trauma was identified, based on analyses of clinical data from 3611 patients who were admitted directly to a level I trauma centre and had hospital stays > or = 3 days. Five system dysfunctions were simultaneously associated (P < 0.05) with death (adjusted odds ratio): adult respiratory distress syndrome (ARDS) (4.9), renal failure (6.7), hyperglycaemia (3.6), recurrent acidosis (4.8) and hypoalbuminaemia (1.8). Mortality increased with the number of system dysfunctions. For the 336 patients with MODS (> or = 2 dysfunctions), mortality was 32.4 per cent compared with 1.3 per cent in the non-MODS group (P = 0.0001). Of the 254 with MODS occurring within 72 hours, mortality was 27 per cent compared with 49 per cent in those manifesting MODS later (P < 0.001). The 175 (52.1 per cent) with organ failure (renal failure and/or ARDS) also had metabolic dysfunction. Seven admission risk factors were independently associated (P < 0.003) with MODS [adjusted odds ratio]: pre-existing condition (3.4), age > 50 (3.1), Injury Severity Score > or = 25 (6.4), hypotension (2.8), acidaemia (2.2), 24 h blood loss > 1 l (3.7), and major base deficit (1.6). Only 13 per cent with MODS had an infection in the 5 days before or at initiation of MODS. Haemodynamic instability, acidosis, blood loss, pre-existing condition, age and serious injury were risk factors independently related to life-threatening MODS, but infection was an uncommon precursor except in late MODS.(ABSTRACT TRUNCATED AT 250 WORDS)