Clinical presentation of Plasmodium falciparum malaria reflects a continuum from asymptomatic to multi-organ manifestation and death. Severe malaria is defined by the World Health Organization as a qualitative variable. We used the multi-organ dysfunction score (MODS) as a quantitative approach for severity in 29 patients with severe and complicated P. falciparum malaria to test its usefulness in discriminating different severity levels. The MODS on admission was highly correlated with the duration of symptoms after admission (r = 0.73, P < 0.001) and the serum level of tumor necrosis factor alpha (r = 0.41, P = 0.03). In addition, the simplified MODS, based mainly on clinical findings, was also correlated with liver and renal dysfunction during hospitalization (alanine transaminase, r = 0.42, P = 0.02; blood urea nitrogen, r = 0.45, P = 0.015). A score >or= 16 was associated with significantly longer disease duration (P = 0.018). Thus, this score might provide a predictive value for morbidity in P. falciparum malaria.