The rarity of Spigelian hernias and the frequent subtle clinical findings can cause an important delay in diagnosis, especially in obese patients. Furthermore it has a high risk of incarceration. When this occurs, a fast recognition and adequate treatment are necessary. Treatment can be primary suture or mesh repair. More recently, the laparoscopic approach has become more popular. We present two cases of incarcerated Spigelian hernia and we give a review of the literature, with specific attention for the anatomical features and pathogenesis.