Fast dissolving oral film of Losartan potassium were prepared and evaluated with an objective to rapid dissolution of drug and absorption which may produce the rapid onset of action in the treatment of hypertension and provides the convenient means of administration to those patient suffering from difficulty in swallowing such as paediatrics, geriatric, and uncooperative mentally ill patients and also improve the bioavailability of the drug. The fast dissolving oral film were prepared using different polymers like polyvinyl alcohol, polyvinyl pyrollidone, hydroxyl propyl methyl cellulose, carbopol, pectin and tragacanth by solvent casting method. The fast dissolving oral film evaluated for folding endurance, swelling index, surface pH, in vitro disintegration time, drug content, drug polymer compatibility (IR Study), and in vitro drug release. The physical appearance and folding endurance properties were found to be good and electron microscopy shows that films are clear, colourless with smooth surface without any scratches. The average folding endurance time within the range of 112 to 208. The drug content showed uniform mixing of drug in all prepared fast dissolving films. The in vitro drug release showed 78 to 96 % drug release within 5 minutes. Drug release obeys the first order kinetics. The prepared films were stable. Hence it can be inferred that the fast dissolving oral film of Losartan potassium may produce the rapid action thereby improving bioavailability and enhance the absorption by avoiding the first pass effect.