The associates of gout-obesity, hypertriglyceridemia, glucose intolerance, and hypertension, strikingly resemble those of insulin resistance. In the present study we determined whether hyperuricemia is associated with insulin resistance and, if so, whether this association can be explained by other components of the syndrome. For this purpose we quantitated insulin sensitivity (euglycemic clamp) in 37 nondiabetic subjects (aged 30-68 yr) exhibiting varying degrees of the metabolic syndrome (body mass index, 21.5-35.7 kg/m2; serum triglycerides, 0.4-22.0 mmol/L; high density lipoprotein cholesterol 0.38-1.86 mmol/L; blood pressure, 190-100/116-60 mm Hg). In simple linear regression analysis, the serum uric acid concentration (range, 182-568 mumol/L) was inversely correlated with insulin sensitivity (rate of glucose utilization; r = -0.61; P < 0.001) and positively with serum triglycerides (r = 0.68; P < 0.001), but not with body mass index, age, or the plasma glucose concentration. In multiple linear regression analysis, both insulin sensitivity (P < 0.05) and serum triglycerides (P < 0.005) were independently associated with the serum uric acid concentration, and together explained 50% of its variation. Addition of body mass index or age to the model did not improve the degree of explanation. Acute elevation of serum triglycerides about 3-fold, of plasma FFA about 9-fold, or of serum insulin about 28-fold had no effect on the serum uric acid concentration in healthy volunteers. The data indicate that hyperuricemia is indeed an inherent component of the metabolic syndrome and could also be used as a simple marker of insulin resistance.