Withania somnifera Dunal seeds yielded a water soluble polysaccharide as D-glucose and D-mannose in 1 : 3 molar ratio by acid hydrolysis method. The individual monosaccharides were identified by GLC, TLC, paper chromatography and separated by column chromatography. It consumed 1.30 moles of iodine by iodometrically. Its IR spectral data (KBr) indicated that the a-type linkages in D-glucopyranose units at non-reducing ends while b- type linkages in the backbone or main polymer chain with D-glucose and D-mannose units. It was identified by their melting points, preparation of derivatives, nature of the constituent sugars and preliminary analysis of polysaccharides. Keywords : Polysaccharide