Cyclooxygenase (COX) and lipoxygenase (LO) metabolic pathways are emerging as key regulators of cell proliferation and neo‐angiogenesis. COX and LO inhibitors are being investigated as potential anticancer drugs and results from clinical trials seem to be encouraging. In this article we will review evidence of COX‐2 and 5‐LO involvement in cancer pathobiology, propose a model of integrated control of cell proliferation by these enzymes, and discuss the pharmacologic implications of this model.—Romano, M., Clària, J. Cyclooxygenase‐2 and 5‐lipoxygenase converging functions on cell proliferation and tumor angiogenesis: implications for cancer therapy. FASEB J. 17, 1986–1995 (2003)