Two mutagenic reagents, Diethyl sulphate (DES) and sodium Azide (SA), were used to study their effects on the morphological characteristics of Tagetes erecta (L.) cvs. Petite Yellow and Hawaii , as well as  the possibility of  mutation induction  in the M1 and M2 generations. Seeds were treated with different DES and SA concentrations : 0 (distilled water) 1000, 2000, 3000, 4000 and 5000 ppm.  for six hours. DES mutagen at low concentration (1000 ppm.) increased the seed germination percantage, while high concentrations (2000 - 5000 ppm.) decreased it .  No Petite Yellow plants were survived after being treated with the high concentration (5000 ppm.) treatment .  The DES concentrations of 1000, 2000 and 4000 ppm   caused decreases in the plant height of both cultivars in the M1- generation. The DES doses from 2000 to 5000 ppm. significantly decreased the plant height in M2- generation in Hawaii Cv.  There were no significant increases in the number of branches per plant in Petite Yellow , but there were significant differences in Hawaii in both generations. The concentration of 2000  ppm. DES  significantly  delayed the flowering in the M1- generation of Petite Yellow  while 1000 and 5000 ppm. concentrations delayed the flowering in the M1-generation of Hawaii . DES concentrations of 3000 and1000 ppm markedly  increased the  dry weight in the M2- generation of  Petite Yellow and Hawaii plants respectively.                 SA mutagen at low concentration (2000 ppm.) significantly  increased the percentage of germinated seeds, of Petite Yellow in the M2- generation.  There were no significant differences among the treatments on plant height of Petite Yellow , while there were significant differences in both generations of Hawaii . There were no significant differences between the effects of the different treatments on the number of branches and the number of days to flowering  in both cultivars . However, there were significant differences among  the treatments on the number of inflorscences per plant. The differences were not significant for the dry weight  of  both cultivars in both generations .                 Generally, the results had also indicated that DES and SA was effective in inducing morphological changes and mutations , and the induced changes were found to affect the following characters ; growth habit, flower colour and the number and size of ray florets .