Analytical method was developed for the estimation of Fosamprenavir drug substance by liquid chromatography. The chromatographic separation was achieved on C18 column (Symmetry 75*4.6mm, 5um) at ambient temperature. The separation achieved employing a mobile phase consists of 0.1% v/v Trifluoro acetic acid in Water: Acetonitrile. The flow rate was 1.0 ml/ minute and ultra violet detector at 260nm. The average retention time for Fosamprenavir found to be 1.93 min the proposed method was validated for selectivity, precision, linearityand accuracy. All validation parameters were within the acceptable range. The assay methods were found to be linear from 50-150µg/ml for Fosamprenavir.