Identification of candidates for early cardiac transplantation and of those who can wait is important, particularly in patients (pts) with idiopathic dilated cardiomyopathy (DCM). To evaluate the significance of thallium-201 perfusion defect (PD) and age in prognostication, 70 DCM pts underwent thallium scan as well as clinical and hemodynamic examination. Results (1) An abnormal PD was present in 22 of 36 young pts (61%) aged <60 years and in 25 of 34 elderly pts (74%) aged <60 years (ns). (2) In the uni-variate analysis, PD was a significant predictor of cardiac death only in young DCM pts (p = 0.0031). Stepwise discriminant analysis also revealed that PD was again a significant predictor in young pts (Wilks lambda 0.4958, chi-square 14.733, p = 0.0224), although it was not more important than the history of synco’pe or stroke in elderly DCM pts. (3) During 55 ± 41 months, 20 pts had disease-related mortality. In young DCM pts, 5 years survival rate was better in pts without than in those with PD (1.0 vs 0.56, respectively), although it was not affected by PO in the elderly (0.67 vs 0.66). Conclusion Scintigraphic prognostication is important in DCM patients aged <60 years who could usually be candidates for cardiac transplantation. Absence of thallium perfusion defects may indicate good long-term prognosis.