Embryonic stem cells and bone marrow mesenchymal stem cells can be induced to differentiate into cardiomyocytes. Techniques to purify and transplant regenerated cardiomyocytes have been developed, and transplanted regenerated cardiomyocytes are capable of residing in the heart of recipients for long periods. Advances in tissue engineering technology have enabled the production of cardiomyocyte cell sheets for transplantation treatment of heart failure, without the need for a donor, and this has now reached the preclinical stage. The treatment of heart failure using cytokines to mobilize stem cells has also been explored. (Circ J 2005; 69: 1431 - 1446)