Isolated colonic tuberculosis (TB) is rare, and the symptoms are nonspecific making early diagnosis and management difficult. Although colonoscopy and biopsy is an important diagnostic modality, the features are variable and the distinction from other conditions of the colon, especially Crohn's disease and cancer, may be impossible without surgical resection. We report a case of ascending colon TB which was mistaken for colonic cancer during colonoscopy, with non-specific results on biopsy. The diagnosis was finally made when the histopathology report was received. The diagnostic dilemma of colonic TB is discussed.