This paper provides new estimates of international trade in services for mode 3 (foreign affiliates' sales in a host country) for four major OECD countries, thanks to the harmonisation of FATS statistics with conventional international trade ones (trade recorded in the balances of payments - modes 1 and 2), using the CEPII's exhaustive CHELEM-BAL database. The results show that sales by foreign affiliates abroad account for the bulk of international trade in services. Technological changes are speeding up the globalisation of the tertiary sector. These new areas of trade are still dominated by the Northern countries, whose service surpluses offset some of their declining competitiveness in manufacturing markets.