The roots of durum and bread wheat were treated with ٠,٢٪, ٠,٤٪, ٠,٨٪ and ١,٢٪ of the herbicide (٢،٤ - D + MCPA) for ٥, ١٠, ١٥ and ٢٠ hours. As the period of treatment increased, the effect on mitotic rate and mitotic phases was increased; this was indicated by the correlation coefficient. Durum wheat gave higher correlation coefficient. Chromosomal aberrations were noted during anaphase as a result of the treatment with ٠,٢٪ concentration. Mitosis was fully blocked and various genetical aberrations were observed as, multinuclei, separation of DNA pieces and distraction of genetical material appeared at higher concentration.