Serum CA 125 and CA 19-9 were presurgically measured in 40 patients with ovarian carcinoma and in 108 with benign ovarian pathologies. The sensitivity for ovarian carcinoma of CA 125 (cut-off value = 65 U/ml) and CA 19-9 (cut-off value = 40 U/ml) were 67.5% and 37.5% respectively. In particular serum CA 125 was elevated in 71.9% of non-mucinous and in 50% of mucinous carcinomas, while serum CA 19-9 was high in 25% of non-mucinous and in 87.5% of mucinous malignancies. The correlation of CA 19-9 with mucinous histotype was significant. Elevated serum levels of CA 125 and CA 19-9 were observed respectively in 14.7% and in 13.8% of benign adnexal masses. The percentages of elevated serum marker levels were significantly higher in patients with ovarian carcinoma than in women bearing benign ovarian pathology (P less than 0.001 for CA 125; P less than 0.01 for CA 19-9). Serum CA 125 and CA 19-9 alone cannot clarify the nature of an adnexal mass. However, the measurement of serum levels of these markers could give additional information to other diagnostic methods, such as ultrasonography, for discriminating benign from malignant ovarian pathologies.