Thiazolidinediones (TZDs) are used as antidiabetic agents in the treatment of type II diabetes. These compounds are ligands for the nuclear hormone receptor PPARgamma, which is highly expressed in adipose tissue. PPARgamma acts as a molecular switch in the process of fat cell development. The quest for the ideal antidiabetic agent is challenged by the need to develop PPARgamma ligands that improve insulin sensitivity, but do not promote fat cell formation. A newly described PPARgamma ligand may represent an initial step in this direction and could lead to improved agents for treating insulin resistance in type II diabetes.