Metformin HCl is an oral anti-diabetic drug from the biguanide class. It is the first-line drug of choice for the treatment of type 2 diabetes, particularly in overweight and obese people and thosewith normal kidney function. Metformin is the most popular anti-diabetic drug in the United States and one of the most prescribed drugs in the world.Metformin Hydrochloride extended release(ER) formulation 1000mg is necessary to achieve a steady state blood level or tissue level for an extended period, which will be therapeutically effective and non-toxic. In this context sustained/controlled drug delivery systems delivers the drug almost at a predetermined rate either systematically or locally for a specified period of time,sustaining the duration of therapeutic activity and reducing adverse effects. Linear and reproducible release similar to that of Fortamet ER 1000 mg tablets was achieved for optimized formulation (f2 >50) independent of hydrodynamic conditions. The effect of differentformulation variables, namely, ratio of drug to osmogent, membrane weight gain, and level of pore former on the in vitro release was studied.In Osmotic technology systems, osmotic pressure provides the driving force to generate controlled release of drug. In this system a tablet containing a core of drug surrounded by a Semipermeable membrane, which is permeable to water, but not to drug. When this device isexposed to water or any body fluid, water will flow into the tablet owing to the osmotic pressure difference.The main factors of osmotic technology are drug solubility, Osmotic pressure, Delivery orifice,coating membrane. The water soluble polymers like povidone (PVPK-90) and Sodium lauryl sulfate are mainly used for Osmotic technology in this Elementary Osmotic Pump (EOP).By observing the pharmacokinetic characteristics and requirements of Metformin HCl, it is clear that ER Osmotic formulation of Metformin HCl is necessary. So this present research is aimed to investigate the possibility of developing ER tablet dosage form for Metformin HCl. The drug release by Metformin HCl ER tablets by osmotic technology is around 85% in 20 hrs. The optimized formulations were subjected to stability studies as per International Conference onHarmonisation (ICH) guidelines and formulations were stable after a 3 month study.