If the cytological screening test is to be used for the detection of cancer in apparently normal persons, a thorough understanding of the significance of the in situ lesion is imperative. The experiences with large unselected populations and with rescreenings in women having a previous negative smear indicate a preponderance of carcinoma in situ. Reporting as an atypical finding the presence of normal glandular cells in smears of postmenopausal women may be of assistance in the detecting of adenocarcinoma of the endometrium. False-positive reports, if measured by negative biopsy diagnosis, were at most 9.3%. By use of a complete kit sent directly to the physician it is also feasible to reach a large rural population solely on a "mail-order" basis. A notable advantage of this system is the lack of infringement on the "doctorpatient" relationship.