Endometriosis is a disease that affects approximately 5.5 million girls and women in their reproductive years in the United States and Canada. During the menstrual cycle, the endometrial lining of the uterus thickens in preparation to receive a fertilized egg. If fertilization does not occur, this lining sloughs off during menstruation. Endometrial tissue can migrate out of the fallopian tubes and grow outside of the uterus as endometrial implants. This can result in severe pain. Endometriosis is very difficult to detect because most women become accustomed to painful menstrual cycles at an early age. The disease often will go undiagnosed because even with extensive endometriosis it is possible to have minimal symptoms or none at all. Physicians have few diagnostic tools to detect the scars and growths of endometriosis. The only way to confirm the diagnosis and stage of endometriosis is by laparoscopy. Treatment options include hormone therapy and surgery. In the past, the most successful treatment was open laparotomy with excision of the endometrial implants. This article discusses the use of the ultrasonic scalpel to resect endometrial implants through the laparoscope. The patient's perioperative course also is discussed.