Transforming growth factor-s (TGFs) play a prominent role in tumour growth and metastasis by enhancing angiogenesis and suppressing immune surveillance. Despite the increased interest in the effect of TGFs on tumour progression, little is known about the importance of TGF3 and its receptor CD105 in breast cancer. In the present study, we measured the plasma levels of TGF3, CD105-TGF3 complexes and TGF1 in 80 patients with untreated early-stage breast cancer using an enhanced chemiluminescence ELISA method. Of the 80 patients, 14 were histologically confirmed as having axillary lymph node metastases, while the remainder had no evidence of lymph node involvement. The results showed that levels of both TGF3 and CD105-TGF3 complex were significantly elevated in patients with positive lymph nodes compared to those without node metastasis. Furthermore, the levels of both TGF3 and CD105-TGF3 complex correlated with lymph node status. The only patient who died of the disease had very high plasma levels of TGF3 and CD105-TGF3 complex and positive lymph nodes; this patient developed lung metastases within 2 years of diagnosis. No significant correlation was seen between either TGF3 or CD105-TGF3 complex levels and tumour stage, size or histological grade. Plasma TGF1 levels were not correlated with node metastasis, tumour stage, grade or size. Our data suggest that plasma levels of TGF3 and CD105-TGF3 complex may be of prognostic value in the early detection of metastasis of breast cancer.