This paper reports development and validation of a new microemulsion liquid chromatographic (MELC) method for rapid screening of simvastatin and simvastatin acid in human plasma. Plasma samples were injected directly into the HPLC system after appropriate sample dilution with mobile phase. Separations were performed on a 4.6 mm × 150 mm, 5-µm particle, C 18 column, with UV detection at 238 nm. The mobile phase was 0.5% ( w/u ) diisopropyl ether, 1.0% ( w/u ) sodium dodecylsulphate (SDS), 4.0% ( w/v ) n -butanol, and 94.5% ( w/w ) aqueous 25 mM disodium hydrogen phosphate, pH 7.0, at a flow rate of 1 mL min -1 . The method was evaluated according to criteria stated in FDA bioanalytical method validation guidance. The unique approach applied in this paper enables direct analysis of simvastatin and simvastatin acid, so the method can be used to obtain reliable results in a rapid and simple way.