The incidence of cervical adenocarcinoma in situ is increasing in frequency, and our limited knowledge about this lesion presents the physician with a therapeutic dilemma. Treatment for this lesion has included conservative therapy, large loop excision or cold-knife cone biopsy, or definitive therapy consisting of hysterectomy. But, rates of residual adenocarcinoma in situ after cone biopsy with negative margins vary from 0% to 40%, and residual disease rates as high as 80% have been noted when the margins are positive. Despite these recent data on follow-up after conservative therapy such as cone biopsy, it seems that this method is safe and gaining acceptance by many physicians and patients. However, the short follow-up duration and small number of patients limit the conclusions of many studies. The relative infrequency of this diagnosis has precluded extensive clinical experience with the natural history of this lesion.