Angiogenesis is now recognized as a crucial process in tumor development. Copper appears to act as an essential cofactor for several angiogenic growth factors, and both copper metabolism and ceruloplasmin expression are upregulated in many tumors. The role of copper chelators has been investigated in animal models with promising results. New therapies for Wilson's disease (a disease of copper accumulation) have enabled clinical trials of copper chelation to be undertaken. Here we discuss the evidence for a role of copper in angiogenesis and possible mechanisms of action of anticopper agents.