The phenomenon of plant mutualistic symbiosis with microbes may have a positive effect on the improvement of plant tolerance to environmental stresses as well as on the ability of plants to accumulate heavy metal (HM) ions from soil. The influence of Epichloë fungal endophyte (Ascomycota, Clavicipitaceae) on perennial ryegrass (Lolium perenne L.) plants grown in the presence of elevated concentrations of HM ions (Cd2+, Pb2+ and Cu2+) in soil was studied. The presence of Epichloë in the host grass tissues resulted in different accumulation of HM ions in the aboveground parts of the plants. In some cases endophyte infection positively affected ryegrass ability to accumulate HM ions from soil. In plants with (E+) and without (E-) endophytes the hormesis effect was induced by the elevated concentration of Cu2+ ions, resulting in better growth and photosynthesis, as examined by measurements of Chl a fluorescence. The obtained results indicate that based on the laboratory evaluation of the efficiency of HM accumulation, we were able to choose the best associations of perennial ryegrass with endophytes for HM phytoremediation.