In the present work, an attempt has been made to study the sustaining release property of isolated mucilage powder of Plantago ovata by formulating the sustained release tablets of aceclofenac and comparing its efficiency with hydrophilic matrix polymer HPMC K4 M. The drug compatibility with mucilage was checked by FTIR studies and found to be intact and stable. The results of pre-compression studies revealed that they were within prescribed limits that indicate good flowing property. All the formulations were found to be within the acceptable limits of official weight variation test. In all the formulations, friability was less than 1 % indicating good mechanical resistance of tablets. Drug content was found to be within acceptable limits. The formulations were also evaluated for hardness, thickness and dissolution profile. The data of drug dissolution was fitted into kinetic models which revealed that all the formulations followed Peppas release kinetics. The results revealed that the formulation F4 showed sustained drug release up to 12 hours. It also revealed that the isolated mucilage powder of Plantago ovata showed better sustained release over HPMC K4 M. In conclusion, Plantago ovata mucilage, obtained from natural source could be used as a reliable alternative over the synthetic polymers used for sustained release formulations. Key words: Aceclofenac, Plantago ovata mucilage, HPMC K4 M, Release retardant