Colorectal cancer is the third most common cancer in both men and women. Mixed adenoneuroendocrine carcinoma is a rare subtype of colorectal cancer defined as malignant neoplasms in which each component represents at least 30% of the lesion. It was named as Mixed adenoneuroendocrine carcinoma and described by the World Health Organization in 2010. Due to its morphological heterogeneity and the rarity of the condition, it becomes quite challenging to formulate an appropriate treatment plan. In this report, we present a case of 67-year-old man found to have a rectal mixed adenoneuroendocrine carcinoma. We discussed the current management strategies and provide a review of the literature.