Sarcoidosis is a multi-systemic syndrome with an unknown etiology that is characterized by the formation of multiple non-caseating granulomas that disrupts the architecture and function of the tissues. A 58-year-old woman was referred for a skin rash and papules. No specific findings were observed on the initial skin biopsy. On gastroscopy and colonoscopy, gastric erosion and rectal polyp were noted. The rectal biopsy revealed non-caseating granulomas without acid-fast bacilli, indicating a differential diagnosis of Crohn's disease and other granulomatous diseases. A repeat skin biopsy of the papular lesion showed non-caseating granulomas that was consistent with sarcoidosis. The chest x-ray and computed tomography (CT) revealed cardiomegaly without hilar lymphadenopathy. The serum angiotensin converting enzyme level was 122 U/L (normal: 8~52 U/L) with normal liver chemistry as well as normal electrolyte, serum calcium and c-reactive protein levels. Finally, the patient was diagnosed with sarcoidosis with rectal involvement. We report this rare case of sarcoidosis that presented as a rectal polyp.