Intimomedial mucoid degeneration (IMMD) is characterised by aneurysm formation following mucin deposition in the intima and media, with elastic tissue degeneration of the arterial wall. We present a case of a young adult who developed a diffusely aneurysmal aorta and its major branches, which was histopathologically confirmed as intimomedial mucoid degeneration, and a review of the literature. This case report attempts to raise the awareness of the reader to this rare cause of aortic aneurysm and to the bleeding diathesis associated with IMMD that may complicate surgery.