Micellar electrokinetic chromatography (MEKC) using sodium dodecyl sulphate (SDS) in separation buffer has been employed for the separation and determination of acetylsalicylic acid and related compounds in tablets and bulk drugs. Base line separation was achieved by using 12.5 mM sodiumtetraborate decahydrate, 15 mM bone acid (pH 9.0) and 50 mM SDS. Analytical characteristics such as migration time, relative migration time and relative response factor were determined. Drug content in formulations and bulk drugs was determined and the recovery was between 98.6% and 101.5%. All the preparations and bulk drugs examined were found to contain the hydrolyzed and starting material of salicylic acid, in varying amounts.