A stability-indicating RP-HPLC method was developed and validated for the determination trimetazidine in active pharmaceutical ingredient and tablet dosage form. The chromatographic conditions comprised of a reversed phase Enable C18G column (250mm×4.6μm, 5μ), with a mobile phase consisting of methanol-0.05% formic acid (90:10 v/v) with flow rate of 1.0 ml/min. Detection was carried out at 232 nm. The retention time of trimetazidine was found to be 3.8 min. The linear regression analysis data for the calibration plots showed good linear relationship within the concentration range 10–80 μg/ml. The value of correlation coefficient was found to be 0.999. The recovery of trimetazidine hydrochloride was about 95–105%. Trimetazidine dihydrochloride was subjected to stress conditions including acidic, alkaline, oxidation, photolysis and thermal degradation. Trimetazidine is more sensitive to wards acidic degradation. The method was validated as per ICH guidelines.