Diffusion plays an important role in controlled release drug delivery system. Salbutamol sulphate, which is a bronchodilatory drug for asthma, was microencapsulated with a polyacrylic resin: Eudragit RS 100. Drug release data have been analyzed according to various release kinetics like Zero order, First order and Higuchi kinetics. Suice Higuchi mechanism seemed to predominate, the diffusivity rate constant (KBL) and the diffusion coefficient (Da) were estimated according to Baker-Lonsdale method at pH 1.2.