Angiogenesis is a key step in tumor growth, invasion and metastasis. Thus, antiangiogenic therapy was postulated to be an attractive approach for antitumor treatment. Based on today's knowledge, at least three strategies for inhibition of angiogenesis are feasible: (1) inhibition of release of angiogenic factors from tumor cells and/or neutralization of angiogenic molecules that have already been released: (2) inhibition of vascular endothelial cell proliferation and migration, and (3) inhibition of the synthesis and turnover of vessel basement membrane. To date, a number of antiangiogenic agents have been identified. In animal models, treatment with angiogenesis inhibitors has proven antitumor effects. Early clinical experience with angiogenic inhibitors indicates that optimal antiangiogenic therapy in the future is likely to be based on the long-term administration to cancer patients in adjunct to surgery, radiotherapy and conventional chemotherapy.