A die-back fungus isolated from Pinus koraiensis was identified as Cenangium ferruginosum. Mycelial growth of the fungus was the best on PDA among five media tested. Mycelial growths on agar media supplemented with extracts from coniferous trees were relatively better than those on media with extracts from non-coniferous trees. Optimum temperature and pH for the mycelial growth of C. ferruginosum on PDA were 10℃ and pH 5, respectively. When five-years-old P. koraiensis seedlings were artificially inoculated with the fungus for the pathogenicity test of this fungus, 80% of seedlings were infected. and the same symptoms and signs were developed as those of naturally-infected trees.