Acute abdomen due to incarcerated umbilical hernia is a surgical emergency. Acute abdomen secondary to gynaecological conditions is not uncommon. However, acute abdomen due to incarceration of a gynaecological tumour in an umbilical hernia is rare. A 25-year-old nullipara was admitted to the accident and emergency unit with a history of recurrent lower abdominal pain and abdominal swelling for 4 weeks. Pain worsened within the last 24 h necessitating presentation. Examination revealed a low-grade pyrexia, tachypnoea, an umbilical swelling with generalised abdominal tenderness, and a pelvic mass more in the right iliac fossa. Bedside abdomino-pelvic ultrasound scan confirmed bilateral adnexal masses with features suggestive of mature teratoma. A diagnosis of acute abdomen secondary to ovarian tumour accident was made. An emergency exploratory laparotomy revealed a huge right ovarian tumour incarcerated in an umbilical hernia. She had bilateral ovarian cystectomy and herniorrhaphy. Gynaecological tumours presenting as incarcerated or strangulated hernias are extremely rare but can be a cause of acute abdomen in women.