Background: It has been well known that in animal model of cardiomyopathy apoptosis is related to myocardial damage, eventually leading to heart failure. However, the expression of apoptosis in human cardiomyopathy has not been fully studied yet. The aim of this study was to elucidate whether the apoptosis is expressed in human hypertrophied (LVH) and dilated cardiomyopathy (DCMP). Methods: 13 patients(M:F=13:0, mean age=45짹16 yrs, 5 with LVH, 8 with DCMP) who underwent endomyocardial biopsy were enrolled. The expression of Bcl-2 that are known to have anti-apoptotic function and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) as a marker of apoptosis were analyzed using immunohistochemical staining. The positively stained areas of Bcl-2 were calculated by image analysis program(Image Pro-Plus 4.5) and the TUNEL positive cells were manually counted under X 200 magnification at 2 fields and divided by the total number of myocytes. Results:1.The volume fraction of Bcl-2 was 0.4266짹0.347 in LVH group and 0.42585짹0.332 in DCMP group (p=1.0). 2. The expression of TUNEL-positive cells was 24.4%짹8.2 in LVH group and 30.2%짹5.2 in DCMP group (p=0.284). 3. There was no significant difference in the expression of Bcl-2 between LVH and DCMP. Conclusion: We confirmed the expression of apoptosis in human myocardial tissue and that the apoptosis of myocytes is similarly expressed in LVH as well as DCMP.