Twelve cases of tubal pregnancy after sterilization operations are reported and the pathogenesis is discussed. Diagnosis is sometimes delayed because of the history of previous sterilization. It is paradoxical that the diagnosis of an intrauterine pregnancy after tubal sterilization is rarely in doubt yet the possibility of the fertilized ovum implanting in a tube known to have been damaged is sometimes overlooked. It is suggested that bilateral salpingectomy is the correct operative treatment for this condition.