AbstractThe present article deals the entropy generation due to heat and mass transfer of an unsteady MHD flow of a Casson fluid squeezed between two parallel disks. The upper disk is taken to be impermeable and the lower one is porous. The flow field equations are reduced to non-linear ordinary differential equations by using similarity transformations and the resulting ODE problem is solved by shooting technique with Runge-Kutta 4thorder method. The effects of various non dimensional fluid and geometric parameters on the velocity components, temperature, concentration, entropy generation number, Bejan number, skin friction and Nusselt number are illustrated through graphs and tables. It is noticed that the temperature of the fluid is enhanced with Eckert number, whereas the concentration of the fluid decreased with Casson fluid parameter. The present study is applicable to nuclear engineering cooling systems, wire and blade coating, extrusion of polymer fluids, optical fibers, magnetohydrodynamics and optimization of chemical engineering processes.