A simple stability-indicating isocratic RP-HPLC method was developed and validated for the determination of mycophenolate sodium and its alkali degradation product. Forced degradation of the drug was carried out under thermolytic, photolytic, acid/base hydrolytic and oxidative stress conditions. Alkali degradation product DP1 was isolated and separation of stress degradation products was achieved on a Symmetry C18 (250 × 4.6 mm × 5.0 $\mu$m) column using the mobile phase methanol-acetate buffer adjusted with acetic acid to pH 6.0 (76 + 24, v/v) at a 0.55 mL/min flow rate and 50°C. Data were integrated at the detection wavelength of 251 nm. The method validation characteristics included accuracy, precision, linearity, range, specificity and sensitivity per International Conference on Harmonization guidelines. Robustness testing was conducted to evaluate the effect of minor changes in the chromatographic conditions and to establish appropriate system suitability parameters. Structural elucidation of degraded products was performed by HPLC/MS/MS. The method was used successfully for drug product analysis, dissolution study and determination of the drug's acid, alkali and oxidative degradation kinetics.