Two novel chromatographic methods having requisite precision, accuracy, specificity and robustness were developed and validated for quantitative determination of Olmesartan medoxomil (OLM) in pharmaceutical dosage forms. The first method was based on isocratic reverse phase liquid chromatography using promosil RP C18 column (250 x4.6mm ID,5μm) and mobile phase consists of Methanol : 25 mM Phosphate buffer (70:30 v/v; pH = 4.6) at a flow rate of 1ml/min and detection was achieved with photodiode array detector set at 256nm.The response was linear over a range of 20-140μg/ml (R2=0.9996). The second method involves precoated silica gel 60F254 High performance thin layer chromatography with densitometric detection at 256nm using Chloroform: Acetone: Methanol (7:2:1v/v/v) as mobile phase. The calibration curve ranges between 200-800 ng/spot(R2=0.9984). Validation of method was carried out fulfilling ICH guidelines (Q2R1). Both the methods were applied without any interference from excipients, for determination of drug in coated tablets. It is suggested that the proposed HPLC and HPTLC procedure could be used for routine quality control and dosage form assay of OLM.