A 9-year-old-male British fold cat was presented for a general health check before anesthesia. Clinical and laboratory examinations were unremarkable. Echocardiography showed that the cardiac anatomy and function were normal, and the presence of a dilated coronary sinus (CS), highly suggestive of a persistent left cranial vena cava (PLCVC). Clinicians should keep in mind that PLCVC may be present when a dilated CS is noted by echocardiography, and it could be confirmed simultaneously by agitated-saline-study as a non-invasive and cost-effective diagnostic tool in practice. Further research is required to elucidate whether PLCVC is an accomplice or an innocent finding in cats.