PURPOSE: The molecular determinants of survival in ovarian cancer are poorly understood. Using expression microarrays, we recently found that high expression of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene is associated with prolonged survival in advanced ovarian cancer. TRAIL has also been shown to synergize with chemotherapeutic agents to induce apoptosis in ovarian cancer cell lines. We therefore sought to confirm the association between TRAIL expression and survival in a larger group of women with ovarian cancer. EXPERIMENTAL DESIGN: TRAIL expression was measured using quantitative real-time PCR in 120 epithelial ovarian cancers (11 stage I/II, 109 stage III/IV) and 8 normal ovarian surface epithelial samples. RESULTS: Ovarian cancers demonstrated 10-fold higher mean TRAIL expression than normal ovarian epithelial samples (P < 0.001). Among ovarian cancers, high TRAIL expression was associated with prolonged survival and was 2.2-fold higher in cancers from patients who lived more than 5 years compared with patients who died within 1 year (P = 0.03). CONCLUSIONS: TRAIL expression is higher in ovarian cancers relative to normal ovarian epithelium. High TRAIL expression is associated with favorable ovarian cancer survival, which may be attributable to increased chemosensitivity of cancers that express the most TRAIL. The use of TRAIL to enhance sensitivity of ovarian cancers to therapy represents an appealing molecular therapeutic strategy worthy of further investigation.