Mixed adenoneuroendocrine carcinoma is an extremely rare tumour of gastrointestinal tract, classified by World Health Organisation 2010 as, malignant tumour with mixed adenocarcinoma and neuroendocrine components with at least 30% of each. MANEC’s are highly aggressive tumour with poor outcome. The diagnosis is based on tumour histology and immunohistochemistry. We report here a case of 59 year old female which presented as vague abdominal pain, was diagnosed as with ascending colon malignancy on colonoscopy and tissue biopsy, underwent right hemi-colectomy and later diagnosed as MANEC on immunohistochemistry studies, positive for CK20, CDX2, MUC2, CD56, Chromogranin, Synaptophysin. Due to paucity of cases, little is known about optimal strategy for management of MANEC.