Aims: The aim of the present investigation was to prepare interpolymer complex between Chitosan and Eudragit L100, and to evaluate its performance as a matrix for controlled release of drugs, using Diclofenac sodium as a model. Methodology: Interpolymer complex were prepared by combining different % chitosan solutions with different % Eudragit L100 solutions in different ratios. The formation of interpolyelectrolyte complexes (IPEC) between carbopol and Chitosan was investigated, using turbidimetry and viscosity measurement. The structure of the prepared IPEC was investigated using FTIR spectroscopy and DSC. A Rotary compression press was used to formulate matrix tablets of diclofenac sodium using polymers in physical mixture and IPECs.The amount of Diclofenac Sodium released in the dissolution medium was determined spectrophotometrically at 276 nm. Results: The results of the present investigation confirmed the formation of an interpolyelectrolyte complex between Chitosan and Eudragit L 100. The release of the model drug Diclofenac sodium was significantly controlled from tablets made up of the IPEC as compared with polymers alone and in combination. Release profiles were represented by a mathematical model, which indicates that the prepared system releases drug in a zero-order manner by changing the ratio of the IPEC in the tablets. Conclusion: Controlled release drug delivery systems designed to manipulate the drug release to achieve specific clinical objectives that are unattainable with conventional dosage forms.