OBJECTIVE To characterize a Bartonella strain M9HN-SHQ from a blood culture of cat from Henan Province,China. METHODS The organisms were subcultured in 5% CO2 at 37 degrees C on trypticase soy agar containing 5% sheep blood for 6 to 7 days. We analyzed the isolate using whole-cell fatty acid analysis,Etest for susceptibility testing, random amplified polymorphic DNA (RAPD), pulsed-field gel electrophoresis(PFGE) and sequence analysis of 16S rRNA, gltA, groEL, ftsZ, rpoB, ribC and 16S-23S rRNA intergenic spacer region. RESULTS Isolate M9HN-SHQ stained faintly as a gram-negative rod but was easier to visualize when stained by the Gimenez technique. Most of the biochemical and cellular fatty acid properties of strain M9HN-SHQ were typical for bacteria of the Bartonella genus. The strain was susceptible to Cefotaxime sodium, Rifampin, Ciprofloxacin and other four antibiotics. Genotypic characterization of strain M9HN-SHQ, including RAPD, PFGE was distinguishable from the reference strains of B. henselae, B. elizabethae, B. vinsonii subsp. berkhoffii and B. grahamii. Sequence analysis of the genes from the seven chromosomal regions identified the strain M9HN-SHQ as B. clarridgeiae. CONCLUSION To our knowledge,this is the first report that documents Bartonella clarridgeiae infections of domestic cats in China.