In the present research, a series of magnetic chitosan based composites with the general formula of NixMn1−xFe2O4/CS were synthesized from spinel-type transition metal ferrites [NixMn1−xFe2O4 (where x= 0, 0.2, 0.5 and 1.0)] and chitosan (CS) as a polymer. The structure and composition of the synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The adsorption activity of the synthesized magnetic chitosan based composites was evaluated for the removal of Congo red (CR) dye from aqueous solution. Furthermore, the influence of the Mn content on adsorption capacity of the synthesized magnetic chitosan based composites were studied. The results of adsorption kinetic of CR dye using spinel-type transition metals NixMn1−xFe2O4 and NixMn1−xFe2O4/CS followed pseudo- second order model. The results indicated that 74% of CR dye solution were removed via adsorption using Ni0.5Mn0.5Fe2O4/CS after 180 min. The adsorption performance show that the chitosan based composites can be more efficient than spinel-type transition metals for removal of CR dye. Moreover, the magnetic chitosan based composites can be quickly separated from the aqueous solution by an external magnet after adsorption process.