The present study aims at the formulation of a floating drug delivery system of an antiulcer drug nizatidine using different grades of HPMC (K100, K4M, K15M & K100M) and an effervescent agent i.e. sodium bicarbonate. It was found that the release rate of nizatidine from tablet formulations prepared from HPMC K100LV was very high as compared to that from formulations containing higher viscosity grades namely K4M, K15M and K100M. In the current study, it was also found that overall rate of drug release tends to decrease with increase in concentration of HPMC. These observations are in agreement with the results reported in literature i.e. with the increase in polymer concentration and viscosity grade, the viscosity of gel layer around the tablet also increases leading to enhanced diffusional path length for the drug to follow and thus limits the release of active ingredient.