A numerical study on unsteady, MHD, chemically reacting, free convective, and non-Darcy flow of Casson fluid over a cone placed vertically is presented. The flow regime is influenced by double dispersion effect. The Crank– Nicolson technique is employed to solve the coupled nonlinear partial differential equations. Graphical results are obtained for various controlling parameters present in the governing equations of the problem. The graphical results are very useful to analyze the influence of various controlling parameters on Casson fluid flow. The average skin friction, rate of heat transfer coefficient, and rate of mass transfer coefficient for sundry parameters have been presented in tables below. Results indicate that enhancing the Casson fluid parameter tends to decelerate fluid flow by increasing the plastic dynamic viscosity, whereas it enhances the shear stress in the flow regime. The double dispersion effects play a vital role on sensitive controlling of energy consumptions and species concentration in a small region near to cone and plate. © Springer Science+Business Media Singapore 2016.