A simple, rapid, precise, stability indicating, isocratic reverse phase-high performance liquid chromatography method has been developed and validated for the determination of Zonisamide in bulk and pharmaceutical dosage form. The Chromatographic Separation was achieved by using Enable ODS reverse phase (250 x 4.6 mm, 5 μm particle size) C18G column. Mobile phase consists of mixture of 0.1% (v/v) ortho phosphoric acid and Methanol in the ratio of 30:70 (v/v) and was delivered at a flow rate of 1 ml/min, while the detection was monitored at a wave length of 285 nm. The developed method showed excellent linear response (r2>0.9999) in the range of 10-70 μg/ml. The retention time for Zonisamide was found to be 3.5 mins. The proposed method was validated as per ICH guideline and can be applied for estimation of Zonisamide in pharmaceutical dosage forms in routine analysis.