Blended polyethersulfone/polyimide (PES/PI) membranes for the separation of CO2 from flue gases have been explored. Asymmetric PES/PI blended flat sheet membranes were prepared using phase inversion technique. The proportions of polyimide (PI) in the blended PES/PI membranes were kept within 5-20%. Field Emission Scanning Electron Microscopy (FESEM) investigations showed that the surfaces of blended membranes are highly homogeneous and their cross-sections showed non-porous top and very little porous substructure. FTIR study shows the characteristic frequency shifts at 1140 cm-1 and 1710 cm-1 for PES and PI respectively in the blended membrane composition. The permeability of CO2 increased with the increase in PI content and it slowly decreased with the increase in the pressure.