Right atrial aneurysms were first described in 1955, and subsequently, only a few cases have been reported. The etiology of this condition is unknown. Its comorbidity with cholestasis has not previously been reported in the literature. An 11-month-old baby female, who was an offspring from a first-cousin marriage, was referred to our hospital for investigation of jaundice. She underwent echocardiography because of a heart murmur, and this revealed a giant right atrial aneurysm. In addition, her liver biopsy confirmed the diagnosis of progressive familial intrahepatic cholestasis (PFIC) type 3. Although both conditions are rare, we found their comorbidity interesting and are thus reporting the case.