PURPOSE: A laparoscopic appendectomy (LA) is becoming popular for the treatment of acute and perforated appendicitis. Since it was first described, the LA has been modified many times. We present the result for a new technique of LA, in which the LA is conducted through a single umbilical incision without exteriorizing the appendix to perform the operation. METHODS: A single incision laparoscopic appendectomy was attempted in 25 patients (17 men, 8 women). Under general anesthesia, a wound retractor was inserted through the umbilicus. The appendix was grasped and dissected from surrounding tissues with a single flexible dissector or grasper. After mesenteric dissection with ultrasonic shear, the base of the appendix was ligated with an Endoloop. The appendix was withdrawn into the wound protector and extracted from the abdomen. RESULTS: A single incision laparoscopic appendectomy was completed in 25 patients. No major intraoperative or postoperative complications were encountered. The average duration of the procedure was 50.3+/-21.3 min. The average hospital stay was 4.1+/-2.4 days. CONCLUSION: This new technique, a single incision laparoscopic appendectomy, further improves the minimal invasiveness of a LA because a single incision is used. This procedure is a safe, very minimally invasive procedure with excellent cosmetic results.