Introduction: Methimazole is an active pharmaceutical ingredient effectively utilized in hyperthyroidism. Methimazole inhibits peroxidase as well as iodine interactions with thyroglobulin to produce triiodothyronine with thyroxine. Methimazole shows very low protein binding (1-10%) bounds to plasma proteins and is easily metabolized by the liver. Gastro retentive drug system improve the pharmacotherapy of the stomach by local release of therapeutic agent results in high concentrations of drug at the gastric mucosa, which further sustained for long Aim: In this investigation, efforts were given to developing a sustained release floating matrix tablet of Methimazole. Methodology: Floating matrix tablets of methimazole were prepared by utilizing the direct compression method. Sodium bicarbonate and citric acid were used as gas-forming agents. HPMC K100M along with Ethylcellulose used to retard drug release from the dosage form. Result: Floating matrix tablets of methimazole were evaluated for different quality control tests to improve the quality of the product. In dissolution study of the floating matrix of methimazole formulation Floating matrix tablet (FLM4) shows maximum drug release 96.88 % at the end of 12 hours while FLM-1 shows least 84.33 %. Conclusion: In vitro release study of methimazole floating matrix tablets shows that polymer percentage used in the formula is enough to extend the release of the drug for at least 12 hr.