Background: septic arthritis caused by Pseudomonas aeruginosa is uncommon in the immunocompetent older population, despite its occurrence in younger patients with open injuries and in intravenous drug abusers. Case Report: here we report a case of septic arthritis caused by P. aeruginosa complicated by death in an older patient with recently treated Pseudomonas urinary tract infection. Discussion: the diagnosis of Pseudomonas septic arthritis is made on culturing the organism from synovial fluid aspirate. Concurrent septic arthritis and crystal arthropathy is associated with a high mortality.