Forage plants have a high economic value. Tall fescue ( Schedonorus arundinaceus Schreb.) and prennial ryegrass ( Lolium perenne ) are two important perennial and cool-season grasses from Poacea family. Plants of this family have symbiotic relationships with fungi of the genus Epichloe. These fungi have many benefits for their host plant, including resistance to abiotic stresses (drought, salinity, cold) and increased secondary metabolites in the host. Secondary metabolites also change under the influence of stresses and light radiation. Recently, the use of radiation and artificial light in advanced agricultural systems has found a special place. LED lights are one of these artificial lighting systems. The present study was done to evaluate the effect of endophytic-genotype interaction on the characteristics of two species of tall fescue and perennial ryegrass under the dual stress of drought-LED light. This study was done during 2019-2020 in the research greenhouse and Chah Anari farm of Isfahan University of Technology. The plant materials used in this experiment were three perennial ryegrass genotypes (S10 with endophyte and without endophyte and Speedy) and three tall fescue genotypes (75B with endophyte and without endophyte and Silverado), which were obtained from the grass production nursery of Isfahan University of Technology. The experiment was performed in a completely randomized design with three replications. Five light treatments including four LED environments of red, blue, red-blue and white and a natural light environment (greenhouse) were applied. The LED incubators were fabricated in four separate cabinets with one of 100% red light, 100% blue light, 70%red-30%blue combinational light or 100% white light. The light intensity was adjusted to 300 ?Mol photons m?2 s?1. After 2 months, water stress was also applied in three stages. The results of data analysis showed that in general, endophytic genotypes performed better in all traits than their non-endophytic counterparts. On the other hand, genotypes of tall fescue species were superior compared to genotypes of perennial ryegrass species in most of the studied traits after water stress. The survey of the effect of LED lights on plants showed that these artificial lights significantly increased the height, fresh and dry weight of shoots and roots, percentage of cover and plant quality after stress. Measurement of soil moisture also showed that plants treated with LED lights retained soil moisture more than control samples during water stress. This can help increase the plant's resistance to dehydration stress. Examination of the amount of chemical compounds also showed that before the application of water stress, the amount of compounds were higher in the samples of four LED light treatment than the control samples, while after the stress treatment, the compounds increased in the control compared to other samples. In general, water stress increased the chemical composition of the control samples. Since the positive effect of LED lights was shown on increasing the resistance of plants to drought stress, further experiments and studies are recommended about the effects of these artificial lights on plant growth in green space. Keywords: Tall fescue, Perennial ryegrass, Endophyte fungus, Drought stress, LED lights, Interactions.