15(S)-Hydroxyeicosatetraenoic acid [15(S)-HETE] activated signal transducer and activator of transcription 3 (STAT3) as measured by its tyrosine phosphorylation, translocation from the cytoplasm to the nucleus, DNA binding, and reporter gene activity in human dermal microvascular endothelial cells (HDMVEC). Inhibition of STAT3 activation via adenovirus-mediated expression of its dominant-negative mutant suppressed 15(S)-HETE-induced HDMVEC migration and tube formation in vitro and aortic ring and Matrigel plug angiogenesis in vivo. 15(S)-HETE induced the expression of vascular endothelial growth factor (VEGF) in a time- and STAT3-dependent manner in HDMVEC. In addition, neutralizing anti-VEGF antibodies blocked 15(S)-HETE-induced HDMVEC migration and tube formation in vitro and aortic ring and Matrigel plug angiogenesis in vivo. Together, these results show for the first time that 15(S)-HETE-induced angiogenesis requires STAT3-dependent expression of VEGF. In view of these findings, it is suggested that eicosanoids, particularly 15(S)-HETE, via its capacity to stimulate angiogenesis, may influence the progression of cancer and vascular disease.