Allelopathy can affect the growth of cereals and crops in their natural habitats. The current investigation was conducted to evaluate the allelopathic effects of A. arvensis and A. cotula aqueous leaf extracts on Vicia faba. The mutagenic and genotoxic effects of each extract were assessed on mitotic and meiotic cells of faba through a cytogenetic method and polymorphisms in the banding profiles of seed proteins using SDSPAGE. Faba seeds were separately treated with three different concentrations of aqueous extracts (5, 10 and 20%) for 6 and 12 h. According to cytogenetic data, faba exhibits a significant frequency of chromosomal abnormalities as well as obstruction of mitotic and meiotic activities which are concentration and period exposure dependent. At 20% concentration of A. arvensis, the maximum values of the mitotic index (16.73 for 6 h and 16.51 for 12 h) were compared to the control 13.58 and 12.98 respectively.