An adult 22-year-old, male southern cassowary ( Casuarius casuarius ) presented for lethargy, dysorexia and soft feces. Clinical findings under chemical immobilization were unremarkable except for heterophilic toxic changes on blood smear, reduced albumin/globulin ratio and potentially elevated liver parameters. The animal was treated for suspected hepatobiliary insufficiency and received supportive treatment with daily subcutaneous fluids and medication and was monitored with a quality-of-life assessment. It was eventually euthanized after further deterioration. Post-mortem examination revealed vegetative valvular endocarditis, bile duct obstruction, cholangiohepatitis and splenitis with intralesional Enterococcus casseliflavus isolated. This is a first documented case of E. casseliflavus infection in a bird with multiorgan involvement.