Evaluation of estrogen receptors (ER) and progesterone receptors (PR) in breast carcinoma using ER and PR immunocytochemical assays (ER-ICA and PR-ICA) has traditionally been semiquantitative at best. We investigated the use of the SAMBA 4000 image analysis system for quantitation of immunocytochemical ER content in 23 cases and PR content in 20 cases of breast carcinoma after obtaining cytology specimens by fine needle aspiration (FNA). We compared the quantitative assessment obtained by image analysis, the quick score (QS), to the biochemical assay as well as to the ER-ICA and PR-ICA semiquantitative visual histochemical score (H-score). Using Pearson's linear correlation coefficient, we demonstrated that for both ER and PR, the QS obtained by the "area" or "nuclear" programs correlated significantly with the H-scores. However, while the QS obtained on the area program for both ER and PR correlated significantly with the biochemical assay, the QS obtained on the nuclear program did not. The discrepancy might reflect the smaller number of cells evaluated with the nuclear program as compared to the area one. These results show that the SAMBA 4000 system provides an objective means of quantitating ER and PR content by immunocytochemical methods.