AbstractThe Drosophila dorsal vessel consists of two cell types, contractile cardiomyoblasts that form a linear tube‐like structure, and the loosely associated pericardial cells. All heart cells originate during embryogenesis from the early dorsal mesoderm under the influence of external and internal signals. Recently, it was shown that a subset of heart cells arise throughout asymmetric cell division, dependent on the function of Notch, Sanpodo, and Numb. Here, we show that Inscuteable, a multiadapter protein required for asymmetric cell division, participates in the formation of specific heart cells to distinguish between a myogenic (cardiomyoblast) and a nonmyogenic (pericardial cell) fate. genesis 40:218–222, 2004. © 2004 Wiley‐Liss, Inc.