Although most colorectal malignancies are adenocarcinomas from colorectal mucosa, various types of malignant and benign tumors can develop, such as neuroendocrine tumors(NETs), gastrointestinal stromal tumors(GISTs), lymphomas, and sarcomas. Due to their extremely low incidence, little research has been conducted. The purpose was to assess incidence and compare it according to demographic factors using data from Korea National Cancer Registry. Method Data from the Korea National Cancer Registry from 2007 to 2016 were used. The crude incidence, age-standard incidence(ASR) of colorectal non-adenocarcinomas were calculated. Result Over 11 years, there were 267,142 patients with colorectal malignancies. 14,495 patients(5.43%) were diagnosed with non-adenocarcinoma. The ASR was 2.52 per 100,000 in men and 1.56 per 100,000 in women. Lesions were classified according to histologic categories: NET was the most common malignancy(n=10,919[75.33%]). Non-adenocarcinoma was the most common in their 40s and 50s(40-49:3,530[24.35%], 50-59:3,991[27.53%]). Lymphoma was high(54.46%) in patients in teenager. Proportion of NET decreased with age and that of carcinoma increased with age. Carcinoma, sarcoma, and lymphoma were more common among men and melanoma was more common among women. The most common site of nonadenocarcinoma was the rectum(n=11,066[76.34%]). Lymphoma occurred more frequently in proximal colon. Melanoma, GIST, and NET occurred mostly in rectum. 10,155 patients(70.06%) were classified as having localized disease. Conclusion This study is meaningful as it is the first study to examine incidence of colorectal nonadenocarcinoma. Differences in incidence of different lesions based on demographic factors were identified. This study will play a role in cancer prevention and diagnosis projects.