Mutation induction is a step towards creating genetic diversity that is used in conjunction with selection and recombination in the breeding of ornamental plants. The aim of this study was to investigate the effect of the mutagen ethyl methane sulfonate (EMS) on the growth characteristics of four of ficus (Ficus elastica) cultivars. The experiment was factorial in a split-plot design, with cultivar as the main factor in the main plots and two factors of concentration and time in the subplots. The treatments included four Ficus cultivars, concentrations of 0, 0.1, 0.5, 1 and 2% by volume of EMS, and application times of 1, 3 and 6 hours. The results showed that by increasing the concentration of EMS from 0.1% to 2%, the rooting and lethality indices (LD50) decreased from 96 and 94% in the control treatment to an average of 56 and 51%, respectively. Also, increasing the concentration of EMS from 0.1% to 1% by volume caused positive and significant morphological changes in terms of number, length and width of leaves, height and diameter of crown and length of roots in all cultivars; but increasing the concentration from 1 to 2% showed a decrease in growth characteristics compared to the control. Also, by examining the effect of time, it was observed that immersion of cuttings in EMS solution for three hours had a significant effect compared to other treatments. Using the results of the study, four Ficus cultivars underwent morphological changes resulting from the effect of the mutagenic chemical EMS.