This paper informs about the diagnostical accuracy of clinical examination and mammography at the women's Hospital of the Städtische Klinikum Zwickau from 1989 to 1992 when pathological changes of breasts are diagnosed. A total of 508 diagnostical biopsies was performed during this study period. The histological examination resulted in 276 benign breast lesions and in 232 breast cancers. In 432 cases there was a lump palpable in the breast that was noticed at first by more than 60% of women themselves. 288 (56.7%) correct and 220 (43.3%) false diagnoses were established following the clinical examination. This resulted in a sensitivity of 100% with a specificity of 20.3% and an overall accuracy of 56.7%. However, with the help of mammography 386 (76.6%) pathological changes of breasts were found to be correct. 118 mammograms proved to be false. Out of these 90 (17.8%) had a false-positive diagnosis and 28 (5.6%) a false-negative one. The overall accuracy of mammography was 76.6% (sensitivity 87.9%, specificity 67%).