['To investigate whether the production of nitric oxide (NO) relates to the development of renal insufficiency and multiple organ dysfunction syndrome (MODS) in patients with severe sepsis.', 'Prospective study in 23 patients with severe sepsis.', 'Medical and surgical intensive care units (ICU) of three hospitals.', 'Serum nitrate levels, as an indirect parameter of the production of NO in vivo, and scores for renal insufficiency and MODS were determined in patients with severe sepsis during a 1-week period after admission to the ICU. The highest serum nitrate levels were found at 4 h (mean 52 +/- 16 mumol/l) after entry into the study and the levels gradually declined thereafter. Patients with renal insufficiency had considerably higher serum nitrate levels during the study period that patients who did not develop renal sufficiency (MANOVA, p < 0.05). Serum nitrate levels correlated with scores for renal insufficiency (r = 0.60, p < 0.001), and far exceeded the levels that can be explained solely by reduced renal clearance of nitrate. Further analysis showed that serum nitrate levels significantly and positively correlated with scores for MODS (r = 0.44, p < 0.001).'] Does nitric oxide ( NO ) production correlate with renal insufficiency and multiple organ dysfunction syndrome in severe sepsis?