Introduction: Volvulus of the ascending colon is a rare cause of large bowel obstruction and presents because of its mesentery with excessive mobility allowing it to rotate on its axis. It is usually due to a congenital or acquired anatomical variation. Objective: To describe volvulus of the ascending colon as a rare complication in a young patient, whose diagnosis was mistaken for sigmoid volvulus and diaphragmatic hernia. Case report: We present the case of a 27-year-old woman who presented with periumbilical abdominal pain, nausea, vomiting and absence of bowel movements which, according to imaging tests, suggested a sigmoid volvulus and a diaphragmatic hernia at the beginning. After performing a laparotomy, a volvulus of the ascending colon was found up to the middle third of the transverse colon rotated 180º clockwise, a right hemicolectomy was performed plus resection of 10 cm of the distal ileum; it was decided to close the distal colonic end in two planes and perform an ileostomy. Conclusions: The present clinical case aims to show an unusual case of ascending colon volvulus, with initial diagnostic errors; it is intended to inform and instruct medical staff so that they can recognise this presentation of surgical abdomen early, as well as the importance of intervening immediately and avoiding complications.