Simvastatin, a lipid lowering drug whose electrochemical behavior was studied in aqueous alcohol medium at glassy carbon electrode by Cyclic Voltammetry. Cyclic voltammetric studies of simvastatin showed one well defined oxidation peak in Britton Robinson buffer. The effects of scan rate, pH, supporting electrolyte concentration, % of solvent and concentration of simvastatin were examined. The adsorption behavior of sodium dodecyl sulphate (SDS) surfactant on a glassy carbon electrode was investigated. The detection limit of the SDS modified glassy carbon electrode is 2.5X10-7M. The probable reaction mechanism involved in the oxidation of simvastatin was also proposed. The proposed method was sensitive and simple. It was successfully employed to determine simvastatin in pharmaceutical samples.