Transvaginal sonography is an important tool for diagnosing ectopic pregnancy. In this report the transvaginal passage of a needle, with sonographic guidance, into a tubal gestational sac with a live fetus is demonstrated. We injected potassium chloride solution to arrest cardiac activity, terminating the ectopic pregnancy without surgical intervention. The new therapeutic use of transvaginal sonography is an important addition to the treatment of this prevalent disease.