Nuclear matrix protein (NMP), an indicator of apoptosis, was analyzed in patients in multiple organ dysfunction syndrome (MODS). Blood levels of tumor necrosis factor-α (TNF-α) and nitrite/nitrate (NOx)-were also measured in these patients to determine the involvement of these factors in the production of NMP. Forty-six patients : with MODS were studied, 21 (45.7%) of whom died. NMP and TNF-α were measured by enzyme-linked immunosorbent assay (ELISA). NOx was measured by the Griess's method, Marshall's multiple organ dysfunction score (MOD score) was used as an indicator of organ failure. The severity of organ failure was assessed by use of the acute physiology and chronic health evaluation II score (APACHE II score). The number of organs that failed was found to be significantly correlated with the NMP level. The NMP level was also correlated significantly with MOD score and APACHE II score, as well as with TNF-α and NOx levels. NMP and NOx levels in the group that died significantly exceeded those in the surviving group. Results suggest that apoptosis can occur in the presence of MODS, and that its extent increases as the number of failing organs increases. The results also