Some drugs give poor absorption because of a narrow absorption window in the gastrointestinal tract (GIT). To improve the absorption of such drugs in GIT, gastro retentive drug delivery techniques play a vital role. Lamivudine is an antiviral medicine. The floating gastroretentive microspheres were prepared to attain an extended therapeutic action of Lamivudine. Floating microspheres were formulated to prolong the gastric retention and enhancement of bioavailability of the drug candidate. The floating microspheres were formulated using guar gum and xanthan gum as natural polymers. The proposed floating system was evaluated by preliminary evaluation parameters, micrometric investigation as well as Particle size investigation, Percentage yield of microspheres, Drug entrapment efficiency, In-vitro drug release studies, and their kinetics. The formulated microsphere is evaluated in the form of its stable nature. The formulated microsphere was found to be smooth, spherical, and slightly aggregated containing guar gum whereas xanthan gum containing microsphere was found porous, irregular, grossly, and discrete globular. Formulated microsphere gives a good percentage of drug entrapment and practical yields. The floating microsphere prolonged the drug release by up to 12 hrs. The IR spectroscopy of the prepared formulation was shown that the chemical structure of the Lamivudine was unchanged. The prepared lamivudine microspheres presented gastro retentive and extended-release properties. Keywords: Lamivudine; Microspheres; Narrow absorption window; Floating system