A previously unknown basidiomycetous yeast is described for which the name Sympodiomycopsis lanaiensis is proposed. The type strain, LM418(T), was isolated from driftwood collected on a beach on Lana'i (Hawai'i). On the basis of ribosomal DNA sequence analysis [large subunit (LSU), internal transcribed spacer (ITS) 1 & 2, and 18S], LM418(T) belongs to the order Microstromatales, which includes the genera Sympodiomycopsis, Rhodotorula, Microstroma, Volvocisporium and Quambalaria. The strain is described as a new species in the genus Sympodiomycopsis on the basis of morphological and physiological characteristics and the phylogenetic relationship to Sympodiomycopsis paphiopedili. Sexual reproduction was not observed in LM418(T). GenBank accession numbers for nucleotide sequences of regions of the LSU, ITS and 18S regions of the ribosomal operon in LM418(T) are DQ990016, DQ990017 and DQ990018, respectively. LM418(T) has been deposited in the DSMZ as DSM 18755, in the ATCC as MYA-4092, in the Agricultural Research Service Culture Collection as NRRL Y-48466, and the Centraalbureau voor Schimmelcultures as CBS 10858.