Abstract: The transcriptional coactivator p300 functions as histone acetyltrasferase that regulates transcription via chromatin remodeling and is important in the processes of cell proliferation and differentiation in cardiac myocytes.p300 was involved in the pathological process of cardiac hypertrophy and was thought to be involved in cardiac myocyte growth through myocyte enhancer factor 2（MEF2）and GATA-4dependent transcription. The concept of inhibiting p300 histone acetyltransferase（HAT）is to blunt hypertrophy and reduce the rate of decompensation in the heart failure. Understanding precise mechanisms of p300 in the cardiac hypertrophy will highlight the importance of monitoring the cardiovascular impact of drugs that potentiate p300 activity on molecular pathways for hypertrophy and the heart failure.