Among 228 patients who had previous treatment for carcinoma in situ of the cervix, most by hysterectomy, 3 recurrences in vaginal stumps were detected in women age 36, 46, and 56. In another case a carcinoma in situ of the cervix was found in a 25 year old patient who had a diagnostic and therapeutic conization because of desire for childbearing. The histology of the cone showed no residual carcinoma. Concommitent to the recurrent carcinoma in situ of the cervix a carcinoma of the vulva was detected. Recurrences of carcinoma in situ could occur because of incomplete resection of primary lesion. Wrong classification in the laboratory is possible if the invasion is missed on the microscopic examination and the case therefore receives the wrong treatment. Recurrences which are not true recurrences could arise from multicentric atypical foci of the squamous epitheleum of the -ower female genital tract. These considerations lead to the following recommendations: 1. When the suspected diagnosis carcinoma in situ of the uterine cervix is made a large enough cone biopsy which is appropriately marked is obtained and a complete microscopic examination of the cone must be obtained. 2. A hysterectomy with a large vaginal cuff is the treatment of choice. 3. A careful workup of the operative specimen in the microscopic laboratory is expecially essential. 4. A patient with such previous treatment for carcinoma in situ of the uterine cervix must be urged to continue with regular preventive examinations for cancer. The vaginal stump must be regularly re-examined both by colposcopy and by cytology.