Background: Cardiac troponin T (cTnT) is useful biomarker in patients with chronic heart failure (CHF). However, its clinical use is limited by the low sensitivity of the conventional commercial assay system. Recently, a highly sensitive cTnT (hs-cTnT) assay has become commercially available. Methods and Results: To compare the prognostic value of conventional cTnT and hs-cTnT in patients with nonischemic dilated cardiomyopathy (DCM), hemodynamic parameters and the serum levels of conventional cTnT, hs-cTnT and brain natriuretic peptide (BNP) were measured in 85 consecutive CHF patients with nonischemic DCM and then these patients were followed for a mean of 4.1 years. During long-term follow up, there were 20 cardiac deaths. In 85 DCM patients, conventional cTnT was elevated (≥0.03ng/ml) in 4 patients (5%) and hs-cTnT was elevated (≥0.01ng/ml) in 46 patients (54%). In non-survivors (n=20), conventional cTnT was elevated (≥0.03ng/ml) in 2 patients (2%) and hs-cTnT was elevated (≥0.01ng/ml) in 17 patients (85%). In the stepwise multivariate analyses, a high plasma level of BNP (P=0.002), low left ventricular ejection fraction (<30%, P=0.012) and high hs-cTnT (≥0.01ng/ml, P=0.006) were independent significant prognostic predictors, but conventional cTnT (≥0.03ng/ml) was not. Conclusions: The findings of the present study indicated that a high serum concentration of hs-cTnT is a useful prognostic predictor that is independent of LVEF or BNP in CHF patients with non-ischemic DCM, suggesting that an increased hs-cTnT concentration sensitively reflects ongoing myocardial damage. (Circ J 2011; 75: 656-661)