A novel stability indicating liquid chromatographic assay method was developed and validated as per ICH guide lines for the quantitative estimation of Mestranol in Tablet formulation. An isocratic reverse phase LC-method was developed using Hypersil ODS C18, 150 x 4.6mm, 5µm column and a mobile phase comprising of a mixture of (0.01M Tri-ethyl amine PH 2.16±0.1)Acetonitrile: Phosphate buffer (25:75v/v). The UV-detector set at 224nm with flow rate of 1ml\ min-1. The method is linear between 30µg mL-1 to 70µg mL-1 with r2 value as 0.998, the limit of detection (LOD) is 0.001µg ml-1 and limit of quantification (LOQ) is 0.003µg ml-1. The Accuracy of the method was found to be in the range of 99.86% to 100.98%. The method precision %RSD were less than 2. Stress degradation studies were done for acid, base, H2O2and heat. The Proposed method was found to be Linear, precise and accurate for the quantitative estimation of Mestranol in Tablet and can be used for commercial purposes.