Thiamin phosphate synthase (TPS) is a bacterial protein involved in the biosynthesis of thiamin pyrophosphate (TPP), the active form of thiamin (vitamin B1) which is an essential component of the human diet. TPS catalyzes the coupling reaction of pyrimidine pyrophosphate and thiazole phosphate to form thiamin phosphate (TP). MtTPS is a 23 kDa protein and forms a dimer. The crystal structure of thiamin phosphate synthase from Mycobacterium tuberculosis (MtTPS) was determined at 2.35 Å resolution. Thiamin phosphate synthase has an α/β structure with a triosephosphate isomerase (TIM barrel) fold. The MtTPS structure clearly shows that it is very similar to the structure of Bacillus subtilis TPS. The active site of MtTPS is highly conserved when compared to BsTPS and a phosphate group is bound in approximately the same position as in BsTPS.