From 1988 to 1993 we treated 1,310 cases of fine needle aspiration cytology of breast lesions. The results were positive for malignancy in 218, suspicious in 134, negative in 857, and inadequate specimen in 101. Histological examinations were performed in 461 cases; 243 malignancies and 218 benign lesions. The cytological diagnosis of these cases was positive in 211, suspicious in 91, negative in 142 and inadequate specimen in 17. The cytologic diagnosis of the cases of histological malignancy was positive in 198, suspicious in 24, negative in 17 and inadequate specimen in 4. Therefore we have 17 false negative cases. The histological diagnoses in these cases were scirrhous carcinoma (7), papillotubular carcinoma (6), invasive lobular carcinoma (2), mucinous carcinoma (1) and angiosarcoma (1). There were 13 cases of cytologically false positive cases; the histological diagnoses were fibroadenoma (4), mastopathy (4), papilloma (3), adenosis (1) and xanthogranuloma (1). For over six years, we have used a computer system incorporating both cytologic and histologic records. This system is very useful in quickly review the correlations of cytologic-histologic diagnoses. In addition to this system, a close relationship between clinical to pathological department is necessary in the quality control of diagnostic cytology.