A green sea turtle, Chelonia mydas, was found stranded in the Laguna Madre of Padre Island, TX, with reduced mobility and swelling of both shoulder joints. Radiographs revealed progressive destruction of both humero-scapular joints. Biopsy, cytology, and culture revealed a Streptococcus sp. infection and subsequent inflammation. The animal was euthanized 18 months after stranding due to poor quality of life and a grave prognosis for return to function, despite multiple courses of long-term antibiotics, non-steroidal anti-inflammatories, and physical therapy. Necropsy and histopathology revealed severe chronic fibrinonecrosis of both humeri, with intralesional mixed populations of bacteria. Culture samples taken at necropsy grew bacterial populations that included Nocardia sp., Corynebacterium sp., alpha hemolytic Streptococcus sp., and Gram-negative nonfermenters from both shoulder joints. Septic arthritis coupled with no evidence of external wounds indicates hematogenous spread of bacteria as has been demonstrated in other similar cases involving green sea turtles.