Bak is the proapoptotic Bcl-2 protein family member, forming an oligomerized pore at the mitochondrial outer membrane for the release of cytochrome c from the mitochondria into the cytosol. Due to its apoptosis-triggering role, Bak is considered a potential therapeutic drug target. Notably, eltrombopag, an FDA-approved thrombopoietin receptor agonist, was identified as a novel Bak-binding proapoptotic molecule. In this study, the recombinant Bak protein produced in Escherichia coli was purified and then mixed with eltrombopag at a 1:1.2 molar ratio. Crystals were obtained using the sample, and utilized to collect X-ray diffraction data with a maximum resolution of 1.40 Å. Preliminary diffraction analysis indicated that our crystals belonged to the P6₃ space group with unit cell parameters a = b = 73.5 Å and c = 44.6 Å. In a single asymmetric unit, one protein molecule is present, with a 36.5% solvent content and a 1.94 ų/Da Matthews coefficient.