The bone morphogenetic protein (BMP) family is the largest subfamily of the transforming growth factor-beta (TGF-β) superfamily. Some BMPs are expressed before cardioblast formation and throughout the late stages of heart development. BMPs have crucial roles in a broad range of biological events, including cellular proliferation, differentiation, migration and apoptosis during organ development. At least six BMPs (BMP2, 4, 5, 6, 7 and 10) are expressed in the heart, where they have both independent and redundant functions. Experiments on genetically modified mice have demonstrated the importance of BMP signaling for heart morphogenesis after the mid-gestation stage. Interestingly, BMPs play a dual role in heart development. Precise regulation of BMP inhibition and BMP stimulation is required for proper heart development during the early stage of cardiomyocyte differentiation. Knowledge of embryogenesis is frequently used in studies of stem cell biology. Through the application of BMP signal regulation in cardiac development, many systems for the differentiation of embryonic stem (ES) cells into cardiomyocytes are developed. These results reveal the crucial role of temporal and spatial regulation of BMPs and BMP antagonists in heart development. © 2009 Elsevier Ltd. All rights reserved.