The purpose of the present paper is to study the unsteady two dimensional laminar incompressible flow of non-Newtonian fluid between two orthogonally moving porous disks using the Casson fluid model that is used to characterize the non-Newtonian fluid behavior. Governing partial differential equations are reduced into nonlinear ordinary differential equations by using suitable similarity transformation and then solved numerically by Runge-Kutta-Fehlberg technique. The numerical results are found excellent agreement with the literature published before. Trusting to this validity, effects of different physical parameters are discussed. The study reveals that velocity of the fluid particles increases with an increase in the disk expanding ratio.