Fourteen Chinese Biological Species (CBS) of Armillaria were previously identified in a collection of Chinese isolates. CBS C, F, G, H, J, L, N and O remained unnamed, while the remaining isolates included A. borealis, A. cepistipes, A. gallica, A. mellea, A. sinapina and A. tabescens. CBS F was suggested to represent A. singula based on basidiocarp morphology. In this study, phylogenetic relationships between Chinese Armillaria isolates and those from other parts of the world were determined based on DNA sequence data. Results of this study suggest that CBS F might not represent A. singula, and that A. monadelpha (a name applied to the North American form of A. tabescens by some authors) and A. tabescens should be treated as a single species. Four main phylogenetic lineages, referred to as the A. ostoyae, A. gallica, A. tabescens and A. mellea clusters, were identified on the phylogenetic trees. The unnamed biological species grouped within the “A. gallica cluster” and were phylogenetically closely related. The results of this study contribute to our current understanding of the systematics of Armillaria from South East Asia where these fungi are relatively poorly known.