Disclosed are 3,5-disubstituted-[1,2,4]-oxadiazoles and analogs thereof, represented by the Formula I: ##STR00001## wherein Ar.sub.1, R.sub.2, A, B and D are defined herein. The present invention relates to the discovery that compounds having Formula I are activators of caspases and inducers of apoptosis. Therefore, the activators of caspases and inducers of apoptosis of this invention may be used to induce cell death in a variety of clinical conditions in which uncontrolled growth and spread of abnormal cells occurs.