This paper is an annual publication issued by the Microeconomic Analysis service of the National Bank of Belgium. The Flemish maritime ports (Antwerp, Ghent, Oostende, Zeebrugge), the Autonomous Port of Liège and the port of Brussels play a major role in their respective regional economies and in the Belgian economy, not only in terms of industrial activity but also as intermodal centres facilitating the commodity flow. This update paper provides an extensive overview of the economic importance and development of the Flemish maritime ports, the Liège port complex and the port of Brussels in the period 2004 - 2009, with an emphasis on 2009. Focusing on the three major variables of value added, employment and investment, the report also provides some information about social balance and the financial situation in these ports as a whole. These observations are linked to a more general context, along with a few cargo statistics. Annual accounts data from the Central Balance Sheet Office were used for the calculation of direct effects, the study of financial ratios and the analysis of the social balance sheet. The indirect effects of the activities concerned were estimated in terms of value added and employment, on the basis of data from the National Accounts Institute. In terms of maritime cargo traffic, the downturn recorded during the last quarter of 2008 continued throughout 2009. Direct value added declined in all the ports in Flanders. Maritime branches as a whole contracted. Only the value added of the maritime branches in the port of Ostend remained stable. The non-maritime branches as a whole saw a contraction in all the Flemish ports. It was the port of Antwerp that suffered the most from the drop in the value added. Its maritime branches shrank by nearly one third. While the non-maritime branches were slightly down. The port of Ghent recorded a bigger decrease in the non-maritime branches. Conversely, the value added in the port of Zeebrugge fell more sharply in the maritime branches. Direct employment in ...