Thirteen strains of yeasts were isolated from ambrosia beetle galleries at several sites in Japan. Based on the morphological and biochemical characteristics and phylogenetic analysis of the D1/D2 domain of the large subunit (LSU) rRNA gene of the yeasts, 10 strains were shown to represent a novel species of the genus Wickerhamomyces, described as Wickerhamomyces scolytoplatypi sp. nov. (type strain NBRC 11029(T) = CBS 12186(T)), and were closely related to Wickerhamomyces hampshirensis. The three other strains represented a novel species of the genus Cyberlindnera, described as Cyberlindnera xylebori sp. nov. (type strain NBRC 11048(T) = CBS 12187(T)), and were closely related to Cyberlindnera euphorbiiphila. It is suggested that these species are associated with ambrosia beetles and we consider ambrosia beetle galleries as good sources of novel yeasts.