Previous studies have revealed that some Xylaria species were closely associated with fungus-growing termite nests. However, this relationship had been very rarely investigated and the host-specificity of termite-associated Xylaria was not yet clearly established. 18 Xylaria rDNA-ITS sequences were obtained from fungus combs belonging to 11 Macrotermitinae species from 8 regions. There was low diversity between isolates and 9 different sequences were retrieved. Termite-associated Xylaria were shown to be monophyletic, with three main clades, all including strains from various termite hosts and geographical localities. This new molecular study shows that there is no species specificity with respect to fungus-growing termites which suggests that there may be substrate specialization.