The broad range of plant mutants has resulted in the creation of a new variety of plants that includes food, medicinal and ornamental flowering crops. Marigold are commercially and traditionally harvested for economic, cultural and medicinal uses. In this present mutational study, healthy Tagetes erecta L. seeds were exposed to gamma rays and EMS with subsequent concentrations. My research findings indicate the seed germination, seedling survival and determination of LD50 of the treated seeds alongside the control seeds. The present study reflects that the concentration of mutagen doses is inversely proportional to seed germination and seedling survival. From the above, the lethal dose was calculated and demonstrated that Gamma rays are more efficient mutagen than EMS for Tagetes erecta L.