The present research deals with formulation of micro spheres containing an Anti-cancer drug Imatinib mesylate reduce the frequency of dosing. Imatinib mesylate is a protein-tyrosine kinase inhibitor, useful in the treatment of various types of cancer and used in the treatment of atherosclerosis, thrombosis, restenosis, or fibrosis. Imatinib mesylate loaded micro spheres were formulated by using both hydrophilic and hydrophobic polymers. Polymers are impregmented by Chemical Cross Linking method using like Sodium Alginate and HPMC K100 to develop a sustained release dosage form. The concentrations of cross-linking agent will influences loading of polymers in this formulation. The effect of concentration of cross-linking agent (Glutaraldehyde) in microspheres formulations and its properties investigated. The investigation done by following properties estimations like particle size, bulk density, angle of repose, encapsulation efficiency, percentage of drug loading, SEM,DSC, XRD, biodegradability, and drug release kinetics. Our all formulations shows particle, bulk density, encapsulation, releasing rate in optimized way. The kinetics of Imatnib mesylate release from microspheres were analyzed using four different theoretical models, that is, Zero order, First order, Higuchi, and Peppa's models. Micro spheres prepared with Glutaraldehyde showed different release kinetics depending upon polymer loading/finding capacity. Increasing the polymer concentration decreased the release rate of Imatinib Mesylate from micro spheres because of formation of greater structural strength and more tightly texture with the drug. Besides, microspheres gave an adequate fit to either zero order or first order kinetic models, depending on the extent of cross linking reaction between drug and the cross linking agent. © 2012 Elsevier B.V., All rights reserved.