In Nile Delta of Egypt, the introduced invasive species Ipomoea carnea Jacq. occupies pure and/or mixed stands with poor associates along the banks of canals and drains forming a dense above ground patches. In this study, the impact of I. carnea on floristic diversity and soil chemical properties evaluated. The plant community attributes including species richness and evenness were compared between invaded and uninvaded stands. The allelopathic potential of the aqueous extracts of root, stem, leaf and fruit of I. carnea were examined on seed germination and seedling growth of Echinochloa crus-galli and Portulaca oleracea weeds. Results showed that, the inhibitory effect of I. carnea extracts could be related to the presence of phenolics, flavonoids, tannins and alkaloids, and followed a gradient: leaf> fruit> root> stem. The allelopathic activity of I. carnea coupled with its competitive effect for soil nutrients could contribute to the invasion success and attainment of pure population.