We analyzed the serum concentrations of high-sensitivity C-reactive protein (hsCRP) at the time of diagnostic cardiac catheterization in 198 patients with idiopathic dilated cardiomyopathy (IDC) to evaluate its prognostic value. Patients were dichotomized according to a median value of hsCRP of 2 mg/dL. Predefined study endpoints over 69 +/- 33 months of follow-up included major arrhythmic events and transplant-free survival. Major arrhythmic events during follow-up occurred in 20 of 98 patients (20%) with low, compared to 22 of 100 patients (22%) with high hsCRP (ns). By multivariate analysis, a depressed left ventricular ejection fraction (LVEF) was the only significant predictor of arrhythmic risk. Death or cardiac transplantation was observed in 36% of patients with high, versus 22% of patients with low hsCRP (P < 0.05). By multivariate analysis, hsCRP and LVEF were independent predictors of transplant-free survival. Thus, in this patient population with IDC, hsCRP had independent prognostic value with regard to transplant-free survival, but did not contribute in the stratification with regard to arrhythmic risk.