Activated coagulation factor IX (FIX) attenuated cell adhesion to the extracellular matrix (ECM) and induced apoptosis. This activity was localized to the first epidermal growth factor (EGF) domain, EGF-F9. Experiments with caspase-3 inhibitors revealed that attenuation of adhesion and apoptosis by EGF-F9 were dependent on caspase-3.