Average yield of Rice, Wheat, Maize and Pea crop is very low in Pakistan as compared to world. In present studies the possible role of sunflower allelopathy in decreasing the economic produce of these crops was evaluated. During early growth bioassays, all the test crops were subjected to different concentration of fresh and dry root, stem and leaf aqueous extracts of sunflower variety Hysun 33. Leaf extracts especially in higher concentrations, followed by stem and root, significantly inhibited the studied parameters of all test crops. During field trials sunflower was grown to maturity...