The genus Janibacter comprises nine different species mainly found in the environment. Only two human infections by these microorganisms have been previously reported, one by J. melonis and another one by an undescribed Janibacter sp. Herewith we report the first human cases of infection by J. terrae in four bacteremic patients. The microorganisms were isolated from two consecutive blood cultures taken from four febrile patients with several underlying conditions. All patients were treated with antibiotics, two of them with favorable outcome. Two severely immunocompromised patients died, and one was treated with an antibiotic in vitro active against the isolate. Janibacter terrae was identified by phenotypic and 16S rDNA amplification methods. This report includes also the first data on antimicrobial susceptibility of this opportunistic pathogen. Clinical microbiologists should be aware of this microorganism which can be identified by phenotypic and molecular methods.