Endometriosis is a painful disorder characterized by endometrial tissue outside the uterine cavity. It usually affects the pelvis, but in rare cases it might extend to other parts of the body. The report is based on a case of a 39-year-old woman, who presented symptoms of acute appendicitis and diagnosis confirmed with ultrasonography and a computed tomography scan procedures. Laparoscopic appendicectomy was performed. After entering the abdominal cavity, hemoperitoneum was discovered with no associated pelvic or abdominal lesions. Biopsy confirmed acute appendicitis with endometrial glands and stroma infiltrating its muscular tissue. Patient recovered without complications and was discharged 48 h after surgery. The appendix is rarely affected by endometrial infiltration. The literature describes an incidence of 0.8%, just a few cases have been associated with acute appendicitis; however, none of them are described to present hemoperitoneum, being our patient the first one reported with such complication.