Over past 30 years as the expanse and complication involved in marketing new drug entities have increased, with concomitant recognition of the therapeutic advantages of controlled drug delivery, greater attention has been focused on development of extended or controlled release drug delivery systems. In the present research work an attempt has been made to optimize, formulate and characterize extended-release tablet of Cefaclor. The preformulation studies were performed for the drug (e.g., physico-chemical properties, melting point, solubility etc.). The drug had shown the results under standard specifications. UV spectroscopic analytical method was also performed for quantitative determinations by plotting standard curve. Before this the pure drug was also scanned for the ƛ max value at different concentrations. The pre-compressions parameters and the post compression parameters for the nine formulated tablets were performed. The drug release study of the selected formulations EF3, EF6 and EF9 was performed as those formulations has shown the results within pharmacopoeia limits. The Formulation EF9 was then taken for release kinetic study as it has shown best results among the other three formulations. So, it confirms the drug release by Higuchi diffusion mechanism. From the results, conclusion can be drawn that the formulation consisting 10-12% concentration of hydroxypropyl methyl cellulose K4-M with 1% microcrystalline cellulose and 25% of lactose are considered as ideal for the optimized extended-release tablet formulation for Cefaclor. Keywords: Extended release, Cefaclor, Higuchi diffusion mechanism, PBP, bacterial cell wall synthesis.