In this report, a seven-year-old English Pointer male with Streptococcus dysgalactiae subsp. equisimilis arthritis joint infection is presented. The dog was referred to the Internal Medicine Department Policlinics with the symptoms of anorexia, weakness, swollen joints and ulcerative wounds on testes. On physical examination, the dog was depressed and manifesting discomfort during manipulation of the fore and hind legs' joints. There were palpable effusions of the right carpal, elbow, and tibiotarsal joints. Haematological and serum biochemical analyses showed mild anaemia, moderate thrombocytopaenia, and elevated alanine aminotransferase. As soon as the synovial fluid aspirates were obtained aseptically from the right elbow, radiocarpal, and tibiotarsal joints, they were sent to bacteriological examination. Symptomatic and supportive treatment was initiated immediately. Empirical enrofloxacin therapy was initially started. Bacteria which were cultivated from the synovial fluid aspirates specimen were identified as S. equisimilis. The isolate was found to be resistant to enrofloxacin and susceptible to amoxycillin/clavulanic acid. According to the results of the antimicrobial susceptibility tests, enrofloxacin therapy was terminated and amoxycillin/clavulanic acid therapy was immediately started lasting for four weeks. The dog was treated successfully. To our knowledge, Streptococcus dysgalactiae subsp. equisimilis was isolated from the synovial fluid from a dog for the first time in Turkey, as it is rarely seen in dogs.