Abstract: Laboratory and greenhouse pot experiments were conducted to evaluate the potential usefulness of Oxalis pes-caprae L. as allelopathic ground-cover species for integrated weed management. The effects of the extracts of several tissues and the exudates from living roots of O. pes-caprae plants were tested for their allelopathic activity on several plants. Duckweed fresh weight was significantly inhibited from phytotoxic activity of petiole tissues (and secondly leaves and stems) of O. pes-caprae. For all the kinds of tissues duckweed fresh weight was reduced with increasing extract concentrations. Besides, root exudates of Bermuda buttercup caused 62, 58 and 42% inhibition of the dry biomass production of tomato, oat and lettuce plants, respectively, confirming the remarkable allelopathic activity of this weed.