In the present study, the effects of radiation on MHD free convection from a cylinder with partial slip in a Casson fluid in non-Darcy porous medium is investigated. The surface of the cylinder is heated under constant surface temperature with partial slip. Partial slip factors are considered on the surface for both velocity and temperature. The boundary layer equations are normalized into a system of non-similar partial differential equations and are then solved using a bi-variate quasilinearization method (BQLM). The boundary layer velocity and temperature profiles are computed for different values of the physical parameters. Increasing the Forchheimer parameter decreases the temperature profiles. The decrease of the velocity profiles with the increase in magnetic parameter is more enhanced in the presence of the velocity slip factor. Increasing the Eckert number increases the temperature profiles in both suction and blowing cases. This study considers the unique problem of the effect of transpiration in a Casson fluid in the presence of radiation, a magnetic field, and viscous dissipation. The results obtained in this study are compared with other numerical methods and were found to be in excellent agreement.