Gastro retentive drug delivery systems are the dosage forms which are retained in the stomach for a prolonged period of time and hence improve the bioavailability of drugs. Famotidine, an anti-ulcer drug, have less oral bioavailability (50%) because of its poor solubility in alkaline pH. Therefore, the main objective of present work is to develop floating effervescent tablets of famotidine. The tablets were prepared with polymers like HPMC K4M and HPMC K100M using directly compression technique. The floating tablets were evaluated for uniformity of weight, hardness, friability, drug content, In vitro buoyancy and dissolution studies All the prepared batches showed good In vitro buoyancy. The tablet remained buoyant for 6-10 hours. The tablets with HPMC K100M were found to float for longer duration as compared with formulations containing HPMC K4M. The In vitro dissolution studies confirmed the sustained and non fickian drug release from tablets. Stability studies showed that tablets can be stored at room temperatue.