The present study was conducted to determine the allelopathic effect of the aqueous extracts of Cynanchum acutum, Anagallis arvesnsis, Chenopodium murale, Malva parviflora, Sonchus oleraceus and Portulaca oleracea on the germination and seedling growth of Bidens pilosa. Also, the presence of total phenols, flavonoids, saponins, tannins and alkaloids, were screened in the studied plants. The results indicated that the aqueous extract of Cynanchum acutum, Anagallis arvesnsis, Chenopodium murale, Malva parviflora, Sonchus oleraceus and Portulaca oleracea showed a remarkable allelopathic effect on the growth and germination of Bidens pilosa. The effectiveness of the extract was much higher on Cynanchum acutum, as it is the most effective plant extract inhibit the shoot and root growth of Bidens pilosa followed by Sonchus oleraceus, Malva parviflora, Portulaca oleracea, Chenopodium murale and Anagallis arvensis. The allelochemicals such as total phenols, flavonoids, saponins, tannins and alkaloids present in the studied plants. From the present study, it is concluded that the tested plants can be used as natural source of herbicides due to their inhibitory effect, that results from the presence of different allochemicals