Members in the Bcl-2 family are critical regulators of apoptosis by either inhibiting or promoting cell death. Bim/BOD is a group of three splice variants, BimEL, BimL and BimS, with apparent molecular masses of ~23, 16, and 13kD, respectively. Bcl-2 homology 3 (BH3) domain is a potent death domain. BH3 domain containing pro-apoptotic proteins, including Bad, Bax, Bid, Bik, and Hrk, form a growing subclass of the Bcl-2 family. A novel BH3 domain containing protein was recently identified and designated Bim or BOD in human, mouse and rat (1,2). Bim/BOD interacts with diverse members in the pro-survival Bcl-2 sub-family including Bcl-2, Bcl-xL and Bcl-w. Bim/BOD induces apoptosis. The messenger RNA of Bim is ubiquitously expressed in multiple tissues and cell lines (1,2).