${kappa}-Carrageenan$, an anionic polysaccharide, was employed in tablet formulations and its function as a drug release sustaining agent was investigated. Tablets composed of ${kappa}-carrageenan$ and hydroxypropyl methylcellulose were fabricated by using direct compression method. Lactose and sodium alginate were utilized as controls for ${kappa}-carrageenan$. Drug release experiments performed at pHs 1.2 and 7.4 revealed that ${kappa}-carrageenan$ retains pH-dependent sustained release effects due to its anionic characteristics. Also, the ionic interaction between ${kappa}-carrageenan$ and drugs exerted significant affects on drug release kinetics. ${kappa}-Carrageenan$ was found out to be a useful additive for sustained release tablet formulations.