Eleven strains of yeasts, isolated from galleries of ambrosia beetles in Japan, formerly identified as Pichia acaciae were found to have different sequences in the D1/D2 domain of the large subunit (LSU) rRNA gene. After detailed taxonomic studies including a DNA-DNA reassociation experiment, 11 strains were found to represent a novel species of the genus Pichia. It is described as Pichia porticicola sp. nov. (type strain NBRC 100302(T) = CBS 11715(T)). The eleven strains were isolated from various samples associated with different kinds of insects and trees which were collected in 11 prefectures, from the north to the south of Japan. This species might be a common species in galleries of ambrosia beetles in Japan.