This case report concerns a previously healthy thirty-five-year-old female with complaints of inguinal hernia that ultimately proved to be a retroperitoneal haematoma. The patient suffered from a car accident 5 months before admission and was hospitalized. During her prior hospitalization, explorative laparotomy revealed a haematoma of the mesentery. The haematoma was treated conservatively, with fluid resuscitation and rest. During her second admission, MRI of the inguinal region revealed localized haematoma. During inguinal exploration, a fluid-filled bluish indirect hernia sac was identified and found to be contoured by free-flowing, non-clotting blood. The postoperative course was uneventful, and the patient was discharged six days following surgery.