This paper addresses broad issues concerning taxes on company profit in a globalized world in which companies, capital, and profit can move easily between countries. It considers reasons for national taxation of company profit in such a world, and reviews the development of such taxes in the OECD. The role played by tax havens is discussed and evidence on the responsiveness of companies to differences in taxation across countries is presented. A central issue is the allocation of taxable profit between countries. Existing practice has no clear rationale. Recent proposals for fundamental reform in the EU are discussed.