Oral drug delivery system using sustained release microparticles preparation is a nice option for the methodology expansion and for up gradation purpose. In this present work microspheres containing Losartan potassium with different synthetic and natural polymers, gums like HPMC, PVP, Xanthan gum, Guar gum and Sodium alginate were prepared by Ionic Gelation Method. The influence of formulation factors (drug-polymer ratio and type of polymer) on the morphology, particle size distribution, drug loading capacity, micromeritics properties and the in-vitro release characteristics of the microspheres were investigated.