The role of urokinase plasminogen activator receptor (uPAR) and c-erbB-2 in breast and ovarian cancer was investigated. Eighty patients of breast and ovarian cancer and benign lesions, as well as twenty normal controls were evaluated for the expression of c-erbB-2 by Western blotting and uPAR levels by ELISA. The c-erbB-2 and uPAR showed a significant increase in both types of cancer investigated compared to normal control and benign lesions. The frequency of c-erbB-2 was significantly higher in breast cancer lesions (p < 0.01). Levels of CA15.3 in breast cancer and CA125 in ovarian cancer were significantly higher in cases expressing c-erbB-2 (p < 0.01) than in negative c-erbB-2 cases. The uPAR showed a significant positive correlation with advanced stages of breast cancer (r = 0.7971) and ovarian cancer (r = 0.83662), while significant correlations were found for CA15.3 in breast cancer (r = 0.64967) and CA125 in ovarian cancer (r = 0.83996). Taken together, our data suggest that the c-erbB-2 and uPAR in the sera of ovarian and breast cancer act as valuable markers for the evaluation of the patients preoperatively.