In this work, two chromatographic methods have been developed and validated for the determination of sertindole (an antipsychotic agent) in the presence of its oxidative degradation product. Sertindole was subjected to stress stability studies, including acid, alkali, oxidative, photolytic and thermal degradation. The chromatographic methods included the use of thin-layer chromatography (TLC-densitometry) and high-performance liquid chromatography (HPLC). The TLC method employed aluminum TLC plates precoated with silica gel G.F254 as the stationary phase and methanol-ethyl acetate-33% ammonia (1:9:0.1, by volume) as the mobile phase, and the chromatograms were scanned at 227 nm. The developed HPLC method used a reversed-phase C18 column with isocratic elution. The mobile phase was composed of phosphate buffer pH 3.0-acetonitrile-triethylamine (45:55:0.03, by volume) and run at a flow rate of 1.0 mL/min. Quantitation was achieved with ultraviolet detection at 256 nm. The linearity ranges were found to be 2-14 µg/band and 5-200 µg/mL for TLC and HPLC, respectively. The developed methods were validated according to the International Conference on Harmonization guidelines and were applied for bulk powder and dosage forms.