Allelopathic effects of aqueous extracts of leaves and seeds of Datura stramonium were studied on seed germination and its associated growth and yield parameters of Vigna radiata. Seed germination and its coupled growth parameters viz. vigour index, tolerance index, root and shoot length, fresh and dry weight were found to be decreased appreciably as the concentration of both the extracts augmented, when compared to control. On the contrary the phytotoxicity was found to be increased in both the extracts as the concentration increased when compared to control. The physiological parameters like chlorophyll a, b, total chlorophyll and carotenoid were found to be decreased as the concentration of leaves and seed extracts increased when compared to control. Total protein, carbohydrate and phenol contents were found to be decreased in both root shoot axis and in cotyledon as the concentration of both the extracts increased when compared to control. All the measured yield parameters like number of leaves per plant, number of branches per pant, number of pods per plant, number of seeds per pod and height of the plant were found to be decreased as the concentration of leaves and seeds extracts increased when compared to control. In all the above parameters were studied the maximum and minimum values were recorded in control and 25% concentrations respectively.