The pore conformation of polymeric membranes can be significantly altered upon interaction of the membranes with organic solvents affecting the performances of the membranes. Polymer shows swelling properties to organic solvents. Here, we show that swelling properties of polysulfone ultrafiltration membrane can be significantly altered by hexane treatment resulting in a change in the pure water permeability, macromolecule separation, and porosity. The water permeability of the membranes decreased with the dipping time in hexane. It showed that the rate of decrement in water permeability was about ten times for PS-24 (prepared from 24 %, w/w solution in DMF) compared to PS-15 (prepared from 15 %, w/w solution in DMF) while the % solute (macromolecule) rejection was decreased by about 11-17 % for the membranes. The SEM and AFM techniques also revealed the porosity changes as evident from surface microstructure morphology. Our results represent a method for tuning membrane properties without the synthetic efforts.