The intrinsic apoptotic pathway is controlled by hetero- and homo-typic interactions between members of the Bcl-2 protein family. Pro-apoptotic members Bak and Bax permeabilise the mitochondrial outer membrane, resulting in the efflux of cytochrome c and initiation of cell death.  They achieve this by first forming homo-dimers, which subsequently lead to pore forming oligomeric complexes. The pro-survival members, such as Bcl-2, sequester Bak and Bax by forming hetero-dimers. The third member of the family, the BH3-only proteins, are able disrupt this pro-survival to pro-apoptotic complex and thus indirectly activate apoptosis. BH3-only proteins are also thought to be able to directly activate Bak and Bax to initiate cell death. Here we describe the generation of Bak complexes for structural studies. Detergent induced Bak homo-oligomers of tetrameric size were produced and analysed by gel filtration and blue-native PAGE. Detergents were also able to induce an Mcl-1:Bak complex which could be disrupted by the addition of the BH3-only protein Bim. The addition of Bid and other BH3-only proteins to Bak in the presence of CHAPS also resulted in the formation of a stable Bak homodimer. Thus, a range of conditions have been established for the formation of Bak complexes, both hetero-typic and homo-typic, providing material for future structural studies by x-ray crystallography.