Background and Objectives : Cardiac I-123 metaiodobenzylguanidine(MIBG) imaging is widely used to assess cardiac sympathetic neural function. The QT interval abnormalities reflect local inhomogeneities of ventricular recovery time, and may be related to an imbalance in cardiac sympathetic innervation. We sought to evaluate the relationship between cardiac sympathetic distribution and QT dispersion. Methods : Cardiac I-123 MIBG imaging and 12-lead ECG were obtained from 44 idiopathic dilated cardiomyopathy patients(group A) and 16 control patients(group B). Heart/mediastinum(H/M) ratio, washout rate, and variance of MIBG uptake in 20 segments of left ventricular polar map were calculated. We calculated QT, corrected QT(QTc), QTe and QTp dispersion, and QT complexity(PCAr) in 12-lead ECG using software(QT Guard, ver 1.3, GE Marquette, USA) Results: Compared to group B, the variance of MIBG uptake was higher in group A patients(230.85145.34 vs 106.1233.86 , P<0.001). The QTp dispersion was larger in group A than group B(56.5223.43 vs 36.6722.55 ms, P=0.016). No significant differences were found in other QT-related parameters, including QT complexity. The correlation between variance of MIBG uptake and QTp dispersion was significant(r=0.335, P=0.028). Conclusion: The abnormalities of QT dispersion in 12-lead ECG could be explained by inhomogenous cardiac uptake of I-123 MIBG. We can conclude that cardiac sympathetic nerve distribution might modulate QT dispersion partially.