The aim of the study was to formulate and evaluate sustained release microspheres of water insoluble anti-diabetic drug Glipizide. Drugs that are easily absorbed from the gastrointestinal tract (GIT) with a short half life are eliminated quickly from the blood circulation. To encounter this, the oral sustained (SR) have been developed as these release the drug slowly in to the GIT and maintain a constant drug concentration in the serum for a longer duration of time. Glipizide is commercially available as tablet but causes gastric irritation. The study was undertaken to convert it into multiple unit dosage form which could release the drug uniformly throughout the stomach, suppressing the irritation. Various parameters affecting the behavior of floating multi-particulate in oral dosage form were studied.