Tumor angiogenesis is stimulated by a pro-angiogenic shift in both inducers and inhibitors of endothelial growth. To study this shift, we measured serum and plasma levels of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), endostatin, and thrombospondin 1 (TSP1) in 21 advanced non-small cell lung cancer (NSCLC) patients and 46 healthy control subjects. In addition, we assessed the relevance of these levels to disease outcome. Cytokine levels were prospectively measured in plasma and serum by enzyme-linked immunosorbent assay at three times: before chemotherapy and at 1 and 12 weeks following initiation of chemotherapy. In NSCLC patients, serum VEGF levels (sVEGF) were elevated (p<0.001), whereas serum and plasma TSP1 levels were lower (p=0.012 and p=0.004, respectively) than in healthy control subjects. Pretreatment plasma endostatin and serum bFGF levels were higher in NSCLC patients than in healthy controls (p=0.05 and 0.01, respectively). Change in sVEGF at week 12 after initiation of chemotherapy correlated with response to therapy (p=0.002). Patients with pretreatment sVEGF levels <500 pg/mL had a median survival of 11 months, but those with sVEGF >500 pg/mL had only a 6 months' median survival (p < 0.03). In NSCLC patients, VEGF levels are increased, whereas TSP1 levels are decreased, which may trigger and sustain tumor angiogenesis. High levels of serum VEGF at the time of presentation with NSCLC may predict worse survival.