Diosgenin was isolated from the yam samples of Dioscorea deltoidea collected during May-November; and the data accumulated from the analysis at random collections from various sites carried out for three years in different localities. October collection gave 5.5-6% diosgenin as compared with other periods by summing up the results of three years (1977-80) of the two localities in the temperate forest of Kaghan and Galis Forest Division. Next higher yield was observed in the month of August.