Crohn's disease is a condition of chronic inflammation that potentially involves any location the in gastrointestinal tract; however, Crohn's disease with the primary lesion confined to just the appendix is very rare through out the world. Physicians may not be able the clinically differentiate Crohn's disease confined to the appendix from acute appendicitis, and it may not be distinguishable from granulomatous appendicitis of other causes, according to the histopathology. Therefore, clinical follow-up for assessing additional manifestations and sometimes further investigations are the only means of differentiating between granulomatous appendicitis of other causes and early Crohn's disease of the appendix. We experienced 26- year-old man who underwent ileocecectomy for a presumed diagnosis of an acute appendicitis, which pathologically resulted in a granulomatous appendicitis. The cause of the granulomatous appendicitis might have been Crohn's disease because the patient subsequently developed other manifestations of Crohn's disease, according to the follow-up colonoscopy findings. (Korean J Gastrointest Endosc 2008;37:447-452)