The tpp gene of Saccharomyces cerevisiae encoding thiamine phosphate pyrophos-phorylase, one of the enzymes involved in thiamine biosynthesis, was cloned by complementation with an Escherichia coli thiB mutant. The recombinant plasmid pHG123 was found to contain a 2.8 kb insert fragment. Southern blot analysis showed that the 2.8 kb insert fragment of pHG123 originated from S. cerevisiae. The 2.8 kb insert fragment containing tpp gene was sequenced and only one open reading frame of 654 bp which encodes 218 amino acids was found. The upstream sequences of the coding region contain a potential ShineDalgarno sequence, TATA sequence and CAAT sequence. The downstream sequences have a polyadenylation signal which is common to most eukaryotic genes.