Chemical mutagen, ethyl methane sulfonate (EMS) is an effective and widely used chemical mutagen to induce point mutations at higher frequency at random locations in the genome. In the present study, the effect of different doses of ethyl methane sulfonate (EMS) mutagen on seedling and some plant characters in tomato cv. Arka Vikas was studied so that the most effective EMS dose can be standardized to elicit best response by inducing maximum variability. For this, the seeds of tomato cultivar Arka Vikas were treated with 0.5 %, 0.75 %, 1 %, 1.25 % EMS doses and were evaluated in comparison to the control for seed germination, seedling height, plant height, no. of fruits per plant, fruit weight and early fruit yield per plant. Seed germination and all other characters studied recorded reduction in values with increase in EMS dose showing dose dependent relationship. Probit analysis was carried out using seed germination values to determine the Lethal Dose (LD50) and was 1.17% for Arka Vikas tomato variety. For all the characters studied minimum variance was observed in the control plants and the maximum in 1% EMS treated plants. After standardization of EMS dose, tomato mutant population of about 420M2 families using 1%EMS concentration was developed.Based on primary screening a total of 109 (1.23 %) M2 plants with morphological and developmental altered phenotypes in comparison to control were screened according to IBPGR descriptors for tomato. Such mutant population and mutants will helpful to assign functions to the putative genes, which are generated by the tomato genome sequencing project.