LIM domain-containing proteins play critical roles in vertebrate development and cellular differentiation. Recently, four members of the four and one-half LIM protein (FHL) family have been identified and cloned. One of these, FHL2, is expressed in a restricted manner in the cardiovascular system throughout development into adulthood, suggesting that FHL2 may play an important role in cardiovascular development and function. Here we describe the generation and analysis of mice carrying a null mutation of the FHL2 gene.FHL2-deficient mice are viable and maintain normal cardiac function both before and after acute mechanical stress induced by aortic constriction. These data suggest that FHL2 is not essential for cardiac development and function.