Self-incompatibility in plants prevents the self-pollinated seed production. Lack of self pollinated seeds can prevent pure genotypes production. Perennial ryegrass ( Lolium perenne ) is the useful grass in temperate regions. Recently, symbiotic relationship of this plant with endophytic fungus has been discovered. Given the extensive effects of endophytic fungi on host plants, this study examined the effects of endophytic fungi on self-pollinated seed production of ryegrass plants and some other traits. This research was carried out in 2012-2014 at the Agricultural Research Station at Isfahan University of Technology (Chah Anarii). The genetic materials of the study were 64 clones that included 32 endophyte-infected clones and 32 endophyte-free ones. The clones were collected from different regions of Iran, especially from North and North- Eastern parts of the country. Experiment was carried out based on a Nest and completely randomized block design with two replicates genotypes within each endophyte status had nested arrangement. Morphological and agronomic traits were evaluated and recorded over a period of two years. There was a significant difference for dry weight, number of self-pollinated seeds, selfing rate and number of tillers per plant between presence or absence of fungal endophytes in the first year. The differences between symbiotic plants and endophyte free plants for dry weight, number of cross-pollinated seeds and number of tiller was significant. However height, total weight of seed, number of self-pollinated seed, selfing ratio, number of nodes and grain weight was not significantly different. In some traits such as plant height, dry weight, total seed weight, number of self-pollinated seeds, cross-pollinated selfing ratio and tillers per plant, significant difference was found among genotypes in the first and second years. In the first year of evaluations of the seed weight revealed the most genetic variation coefficient (1.22) in the presence of endophyte, while it possessed the less coefficient of variation (0.84) in the absence of endophytic and it had more variations was found for the number of self-pollinated seeds (1.75). In overall seed weight and number of self pollinated seed in the absence and presence of endophytes had the most variations. In the presence of endophyte in the first year, showed significant negative correlation was found between height and self-pollinated number of seeds. The cluster analysis of the genotypes did not separate symbiotic endophytes of genotype from non-symbiotic ones. Cluster analysis divided genotypes into six groups. Similarly, cluster analysis of second year categorized genotypes in six groups. Factor analysis revealed three factors in which the third one accounted for more than 53 % of the variance between attributes and variables. The first factor accounted for 24.75% of variation and was named as selfing factor. The secand on accounted for 19.17% fo variation named as drying yield factor and the third factor was stored dry yield with 19.53% of variation. In the second year three factor accounted for 55% for variation among traits. In overall, endophte elevated the number of self and cross pollinated seeds in Iranian ryegrass. Variation among perennial ryegrass populations, especially for self-pollinated seeds may allow breeding of this plant for Iran climate condition. Keywords : Perennial ryegrass, Selfing, Cross pollination, Endophyte fungi