Introduction: De Garengeot hernia is an entity mainly diagnosed intraoperatively. It is more frequently observed in women and is defined as the presence of the vermiform appendix inside to femoral hernia. Most femoral hernias are identified based on clinical diagnosis, but diagnostic imaging is necessary for confirmation. Ultrasound, for example, is a valuable tool to characterize the anatomy of the hernia and its content, and to establish surgical planning. Case presentation: A 75-year-old woman attended the general surgery department of a high complexity hospital in Bogotá, Colombia, due to a painful mass in the right inguinal region. The initial ultrasound study showed a femoral hernia containing the incarcerated appendix and periappendiceal fluid in the hernial sac. The patient developed chronic appendiceal inflammation, so she underwent femoral hernia repair with mesh and appendectomy without complications, achieving a satisfactory recovery. Conclusion: Clinical examination may be sufficient to confirm the presence of a hernia in a large number of cases when the diagnostic approach involves the search of inguinal masses with pain. However, to facilitate surgical planning, diagnostic imaging, especially ultrasound with high resolution transducers, is the primary tool to characterize the type of hernia and the contents of the hernial sac.