In the present study, development of Gastroretentive Drug Delivery System (GRDDS) of Losartan potassium, an anti-hypertensive drug was designed to increase the gastric residence time. Formulations were prepared using wet granulation method, employing polymers like HPMC K4M, HPMC K15M, carbopol 934P and sodium alginate. Sodium bicarbonate and citric acid were used as gas generating agents. Tablets were evaluated for various parameters like hardness, friability, uniformity of weight, drug content uniformity, drug polymer interaction studies, swelling index, in vitro floating studies, In vitro drug release and short term stability studies. Drug release analysis on the basis of Higuchi-Korsmeyer model indicated that diffusion is the predominant mechanism controlling the drug release. The drug polymer interaction studies indicated no interaction. The short term stability study showed no significant change.