The enzyme dihydrodipicolinate synthase catalyzes the committed step in the synthesis of diaminopimelate and lysine to facilitate peptidoglycan and protein synthesis. Dihydrodipicolinate synthase catalyzes the condensation of L-aspartate 4-semialdehyde and pyruvate to synthesize L-2,3-dihydrodipicolinate. Here, the cloning, expression, purification, crystallization and X-ray diffraction analysis of dihydrodipicolinate synthase from the pathogenic bacterium Bartonella henselae, the causative bacterium of cat-scratch disease, are presented. Protein crystals were grown in conditions consisting of 20%( w/ v) PEG 4000, 100 m Msodium citrate tribasic pH 5.5 and were shown to diffract to ∼2.10 Å resolution. They belonged to space group P2 12 12 1, with unit-cell parameters a= 79.96, b= 106.33, c= 136.25 Å. The final Rvalues were R r.i.m.= 0.098, R work= 0.183, R free= 0.233.