Computational fluid dynamics simulations are conducted to study the hemodialysis process in separation modules containing hollow fiber membranes. Hemodialysis is the filtration process which removes waste out of the blood. In this work, three-dimensional steady-state laminar flow simulations are conducted to investigate the effect of disk baffles on the performance of the hemodialysis process. The uniformly spaced baffles are placed along the axis of the shell within the dialyzer. The disk baffles of diameter 2.85 dhd were considered, where dhd is the shell hydraulic diameter. The inlet solute mass fraction of the blood solution is fixed at 0.00074, while the inlet solute mass fraction of the dialysate solution varied as 0.004 and 0.007. The blood and the dialysate flow rates are fixed. Our results revealed that the presence of disk baffles in the shell mitigates the concentration polarization and yields higher urea permeation. The higher dialysate concentration solute yields a 41.2% increase in the urea permeate rate compared to the lower dialysate solute concentration.