A validated stability-indicating RP-HPLC method for Leflunomide (LFN) was developed by separating its degradation products on a Schimadzu C18 (250×4.6mm, 5µm) column using methanol and water in the ratio of 70:30 % v/v as the mobile phase at a flow rate of 1.0 mL/min. The method was validated in terms of specificity, linearity, accuracy, precision, detection limit, quantification limit, and robustness. Forced degradation of Leflunomide was carried out under acidic, basic, peroxide, photo and thermal conditions and the major degradation products of acidic and basic degradation. The linear regression coefficients for Leflunomide were 0.995 in the concentration range 4-12 mcg/ml. The relative standard deviations for intra and inter day precision were 0.75% and 0.33%. The specificity of the method is suitable for a stability indicating assay. Keywords: Leflunomide, Method development, Stress testing, RP-HPLC.