A fastidious, slowly growing, strictly aerobic, gram-negative bacterium was isolated from a culture of blood from a 25-year-old man with common variable immunodeficiency. The man had been admitted to hospital with febrile progressive cerebellar ataxia. The use of standard phenotypic schemes did not lead to identification, but sequence analysis demonstrated that the 16S rRNA gene of the isolate was most similar to those of the environmental bacteria Duganella zoogloeoides (formerly Zoogloea ramigera 115) and Telluria mixta. Further characterization of the bacterium by biochemical analysis, electron microscopy, G+C content estimation, and fatty acid analysis demonstrated significant differences between the bacterium and D. zoogloeoides and Telluria species; thus, we propose it as a new taxon with the name Massilia timonae gen. nov., sp. nov.