INTRODUCTION Adult intussusception is rare, and differs from childhood intussusception. Unlike in paediatric population, most adult cases presented to emergency department with intestinal obstruction, and rarely, the actual diagnosis of intussusception is made during clinical setting. Top causes of adult intussusception including due to malignant or benign lesions. Adenocarcinoma is the most common malignant lead point. Due to the rarety of adult intussusception, patients whom presented as intestinal obstruction may be misled by the presentation itself, albeit the causative is intussusception. Computed tomography (CT) is the gold standard imaging for intussusception. CASE DESCRIPTION 81 years old malay man presented to emergency department complained of worsening abdominal pain and abdominal distension for past 1 week associated with history of loose stool mixed with blood and mucus for 2 weeks. Upon clinical examination, the abdomen was mildly distended with minimal tenderness at left iliac fossa. Digital rectal examination revealed large polypoidal lesion felt at rectum. Plain abdominal radiograph showed dilated large bowel loops. No pneumoperitoneum or bowel wall oedema. During colonoscopy surgeon, unable to advance scope beyond the large blackish lesion at the lower rectum, which initially thought as a large polypoidal lesion. Urgent contrasted computed tomography showed telescoping of sigmoid colon into the rectum, extending till mid rectum. The affected bowel wall was oedematous but no actual mass was found. Pneumoperitoneum observed. On exploratory laparotomy noted sigmoid colon intussusception into rectum with ischemic segment of bowel. Sesile polyp in the distal sigmoid colon. Perforation of distal part of the sigmoid colon. Histopathology confirmed the lead point was adenocarcinoma of the sigmoid colon. He made an uneventful recovery post surgery and was discharged well. CONCLUSION Intussusception is often difficult to diagnose with non-specific presentations, clinical findings and physical examination alone. Contrasted computed tomography is the modality of the choice for early diagnosis in detecting intussusception, delineate the causes of the intestinal obstruction, prevent further ischemic of the bowel, and helps in early treatment in malignancy. Complications of the intussusception is also demonstrated well in CT and aids the surgeon in terms of resectability. Treatment usually require resection of the involved bowel segment. Prognosis is depending on its aetiology; good outcome if it’s benign cause and poorest if it’s caused by malignant neoplasm.