Abstract: In a laboratory study phytotoxic effects of aqueous leaf extract prepared from Chenopodium album L. on seed germination of several weeds (Echinochloa crus-galli, Amaranthus retroflexus and Cuscuta campestris), mitotic cell division and coleoptile elongation were studied. Also, the effects of GA and IAA on counteracting the inhibitory effects of leaf extract were investigated. At a relatively high leaf extract concentrations (30 and 50% v/v prepared from 10% w/v of original stock solution), only Cuscuta seed germination was reduced. At 50% leaf extract, seedling growth in Echinochloa and Amaranthus was reduced significantly. In the presence of GA and IAA applied separately, the leaf extract had less inhibitory effects on seed germination and coleoptile elongation respectively. In the presence of leaf extract, the number of mitotic cells in Allium cepa root tips reduced significantly.