We report the case of a 70 year-old-man with history of non-insulin dependant diabetes, arterial hypertension and chronic renal failure in hemodyalisis who was admitted to hospital with a history of fever for three weeks. Aseptic arthritis of the left hip was diagnosed an a surgical debridement was performed. Cultures showed growth of a fastidious gram-negative cocobacilus. The patient was re-admitted because of impaired consciousness, an acute myocardial infarction and fever. Brain CT scan and head MRI were normal as well as cerebrospinal fluid analysis. Final identification of the gram negative rod corresponded to Psychrobacter phenylpyruvicus (formerly Moraxella phenylpyruvicus). Treatment with ceftriaxone was begun. After two weeks the patient died of cardiac arrest. Moraxellaceae family is part of the normal flora of the upper respiratory tract and genitourinary tract. Occasionally Moraxellaceae family is seen as a pathogen. There are only two previous reports of infections due to Psychrobacter phenylpyruvicus, a diabetic foot and an infectious endocarditis, this is the first case of septic arthritis caused by this microorganism.