Feline Infectious Peritonitis (FIP) is a progressive and fatal disease in domestic and wild cats, caused by Feline Infectious Peritonitis Virus (FIPV). The disease is characterized by an immunomediated reaction against the virus in various organs. This work described a case report of fibrinous epicarditis caused by FIPV. A male cat, three years old, died and was received to be necropsied. Grossly, soft, multifocal to coalescing, whitish fibrinous exudate, measuring up the 2 centimeters of thickness, was observed in the epicardium, mostly at the apex of the heart. Microscopically, severe, multifocal to coalescing inflammatory infiltrate was observed in the epicardium, composed mainly by macrophages, plasmocytes and lymphocytes, associated with fibrin deposition. Immunohistochemistry was performed for FIPV and was positive in the areas of inflammation in the epicardium. To the author´s knowledge, this is the second report of epicarditis due to FIPV in a cat. Therefore, epicarditis should be considered a differential diagnosis of cardiac diseases in Feline Medicine.