Red pine (Pinus densiflora) is a dominant tree species in Korean forests. The diversity of endophytic fungi was investigated by isolating fungi from different parts of a red pine tree during the fall and spring seasons. One hundred and fifty-two strains of endophytic fungi were isolated and classified into 42 species belonging to 29 genera. Among these, 74 (49%), 47 (31%) and 31 strains (20%) were isolated from branches, leaves, and stems, respectively. The most frequently isolated species were Daldinia childiae and Biscogniauxia maritima (28.9% and 9.8%, respectively). D. childiae was the dominant endophytic fungus on branches (20 strains) and leaves (19 strains). B. maritima was most frequently isolated from branches. The isolation frequencies on stems of B. maritima (6 strains) and D. childiae (5 strains) were also high. Fifty-seven isolates belonging to 19 species and 17 genera were isolated in the spring, and 95 strains belonging to 35 species and 24 genera were isolated in the fall. D. childiae was the most frequently isolated fungus in both spring and fall (21 and 23 strains, respectively). B. maritima was also frequently isolated in both spring (7 strains) and fall (8 strains).