Angiogenesis, the formation of new vessels, has been reported to play a significant pathogenic role in liver damage-associated hepatitis C virus infection. Most of our current knowledge derives from immunohistochemical studies of hepatic biopsy samples obtained from chronic hepatitis C (CHC) patients. We evaluated whether CHC is associated with elevated serum levels of angiogenesis markers and whether these are modulated by therapy. Vascular endothelial growth factor (VEGF), angiopoietin-2 (Ang-2), and soluble Tie-2 (sTie-2) were determined in the serum of 36 CHC patients, before and after receiving antiviral combination therapy with pegylated interferon alpha-2b plus ribavirin, and in 15 healthy controls. CHC patients showed elevated baseline VEGF and Ang-2 levels. After treatment, both factors were decreased, whereas antiangiogenic sTie-2 was increased, indicating a shift toward an "anti-angiogenic" profile of serum markers in CHC patients. In conclusion, this suggests that serum VEGF, Ang-2, and sTie-2 levels could be useful as noninvasive, mechanistically based markers of response to therapy and disease progression in CHC.