We report on a case of a 68-year-old man who was transferred to our department to undergo surgical treatment of intestinal obstruction and a palpable right-sided abdominal mass. The abdominal computed tomography scan revealed a small bowel obstruction with an incarcerated spigelian hernia. A mesh repair was performed by suturing the mesh to the internal oblique muscle and to the rectus sheath. The postoperative course was uneventful, and no recurrence has occurred during the 2-year follow-up. An urgent operation should be performed as soon as an accurate diagnosis of incarcerated spigelian hernia has been made. Computed tomography should be helpful in order to establish an accurate diagnosis of the incarcerated hernia.