It has been suggested that expression of TGFß1 and its receptors [TGFß receptor type I (TßRI) and TGFß receptor type II (TßRII)] may play a key role in the proliferation and progression of epithelial ovarian cancer. We investigated the biological significance of TGFß1 and its receptors, as well as their association with the tumor response to paclitaxel (PTX) and carboplatin (CBDCA). We studied 24 patients with ovarian cancer, primary peritoneal cancer, or fallopian tube cancer who had undergone surgery and chemotherapy with PTX and CBDCA. Tissues from the primary tumor were examined and the expression of TGFß1, TßRI, and TßRII mRNA was assessed by the RNase protection assay. It was found that TGFß1 mRNA expression was significantly lower in the tumors of patients who had optimal surgery than in the tumors of patients with suboptimal surgery. TGFß1 mRNA expression was also significantly lower in tumors with high sensitivity to PTX and CBDCA than in those with low sensitivity. TßRI mRNA expression was not associated with any clinicopathological factors. Expression of TßRII mRNA was significantly higher in clear cell adenocarcinoma and mucinous adenocarcinoma, while it was lower in serous adenocarcinoma and endometrioid adenocarcinoma. Moreover, it tended to be higher in early-stage tumors compared with advanced tumors. Among TGFß1, TßRI, and TßRII, expression of TGFß1 mRNA was most strongly associated with progression-free survival. When the prognosis of the patients with advanced cancer was compared on the basis of TGFß1 mRNA expression, those whose tumors showed low expression tended to have a better prognosis than those whose tumors showed high expression. It is suggested that TGFß1 mRNA expression is an indicator of tumor sensitivity to standard therapy with PTX and CBDCA, that it can identify biologically aggressive and highly malignant tumors and that it can predict the prognosis of patients with ovarian cancer.