The objective of this paper is a valuation of colposcopy as a screening tool. As database, 392 patients with histologically confirmed intraepithelial neoplasia were used. Colposcopic and cytologic findings were compared with the final histologic diagnosis. The following results were obtained: (1)The colposcopic findings correlated with the histologic diagnosis to a significantly higher degree than the cytologic findings. Depending upon the rate of dysplasia, the colposcopic findings predicted the diagnosis in 84-97%. (2) The false-negative rate of cytology in condylomatous lesions and mild dysplasia was high (39 and 26%, respectively), in particular in comparison with the false-negative rate of colposcopy of 5% for both lesions. Thus, a negative smear does not exclude consistently a dysplasia of the cervix. (3) The false-negative rate of cytology for the high grade lesions (CIN II and CIN III) was 13 and 1% respectively and, thus, lower than in the low grade lesions. There were, however, considerable discrepancies in comparison with the histologic rating of the lesion. In CIN III cytology correlated with histology in only 61%, colposcopy, however, 85% (P < 0.001). Our results demonstrate that colposcopy is an excellent tool for detecting HPV caused lesions especially subclinical lesions and CIN I. Colposcopy is also a corrective for the false-negative cyto-smear rate (about 20-40%). Thus, colposcopy may be used as an effective quality assurance method and an excellent screening method in that colposcopy is superior in grading dysplastic lesions of the cervix. The application of the European terminology was advantageous.