Seed set through self-pollination as the most important reproduction system plays important role in maintaining plants genotype and generating uniform plants in tall fescue ( Festuca arundinaceae ) which is widely used as fodder and lawn. On the other hand, tall fescue has symbiosis association with endophytic fungus ( Neotyphodium coenophialium ), improving forage and seed yield and protecting plants against pests and diseases. Any change in plant genotypes due to cross-pollination may decrease the effect of endophytic fungi. The present experiment aimed to evaluate the rate of self and cross pollination in different genotypes as well as the effect of endophytic fungus on self and cross pollination. Genetic material for the present research included eleven fectuca genotypes along with six genotypes native to Iran arranged in a complete block design with three replications. Nine panicles from each genotype were placed in paper pockets before flowering and compulsive self-pollination was applied. Others plant panicles were left to be open pollinated. Also, peduncle length, leaf flag area, plant diameter, the number of panicles, fresh weight, leaf greenness, percent of pollen grains alive, the number of seeds in self-pollinated panicle, number of seeds in cross-pollinated panicle, self-pollination percent, 100-seed weight due to self-pollination,100-seed weight due to cross pollination and the ratio of seed numbers from self-pollinated panicle to seed numbers from cross-pollinated panicle were evaluated. Results showed that morphological traits including the number of seeds per self-pollinated panicle and number of seeds in cross pollinated panicle had high genetic variation coefficient implying that they are less affected by environment. Results from mean comparisons showed that among studied genotypes, two exotic genotypes of Jaguar2, Silverado and three Iranian genotypes had self-pollination percentage of 66.16, 58.1 and 58.93 respectively. Genotype Monarch exhibited the highest percent of seed set due to cross pollination. These results denoted that it is possible to produce seeds due to self-pollination and subsequently pure lines in exotic and endemic tall fescues genotypes. Factor analysis showed that first two factors account for 85% of variations among traits. The first factor accounted for 80% of traits variance and had substantial contribution due to factor coefficients of number of seeds in self-pollinated panicle, number of seeds in cross pollinated panicle, 100-seed weight due to self-pollination and the ratio of seed numbers from self-pollinated panicle to seed numbers from cross-pollinated panicle. Hence, this factor was called sellfing seed sink. The second factor accounted for 5% of variance having highest contributions due to factor coefficients for the plant diameter, fresh weight and plant length and was nominated as yield factor. In order to evaluate the effect of endophyte fungus on self-pollination and cross pollination rates, two genotypes infected with endopyhte and their noninfected counterparts were used. Data were analysed using a 2*2 factorial test. Analysis of variance results showed that genotypes*endophyte interaction was significant in traits of fresh weight, leaf flag greenness, the number of seeds in cross-pollinated panicle and the percent of seed set due to self-pollination. Results of mean comparison indicated that endophyte infection could increase seed set through self- and cross pollination in tall fescue. Presumably, this may results from changes in hormone balances induced by endophyte fungus which in turn may improve plant seed and forage yield.