Elevated TGF-β3 mRNA expression predicted poor OS and PFS in all women with ovarian cancer (HR, 1.20; 95% CI, 1.05–1.38; P = 0.0083; and HR, 1.20; 95% CI, 1.06–1.37; P = 0.0055, respectively) and in women with serous ovarian cancer (HR, 1.30; 95% CI, 1.12–1.52; P = 0.0008; and HR, 1.48; 95% CI, 1.28–1.71; P = 0.001, respectively). This evidence concerns the gene TGFB3 and ovarian serous adenocarcinoma.