A stability indicating HPLC assay method was developed for the quantitative determination of Sibutramine HCl in bulk and pharmaceutical dosage form. It involved a 250 mm x 4.6 mm i.d 5 µm Phenomenex C-18 column. The mobile phase consisted of phosphate buffer with pH adjusted to 5 with ortho-phosphoric acid and acetonitrile in the ratio of (60:40, v/v) and was pumped at a constant flow rate of 1 mL/min. Measurements were made at a wavelength of 222 nm. The retention time of Sibutramine HCl was found to be 4.52 min. The calibration curve was linear over the range of 2.5-12.5 µg/mL (correlation coefficient (r2) = 0.9990). The limit of detection (𝑆/𝑁 = 3) was 12.12 ng/mL and the limit of quantitation (𝑆/𝑁 = 10) was found to be 36.46 ng/mL. Sibutramine was subjected to different stress conditions prescribed as per ICH guidelines such as acid hydrolysis, base hydrolysis, oxidation with hydrogen peroxide and photolysis. Degradation was not observed in all the tests performed. The evaluation of stress samples was calculated against a reference standard. The method developed was validated with respect to linearity, accuracy and precision.