This article examines the recent development of urbanized areas in Belgium and endeavours to measure the space consumed by some of the important human activities: industrial operations, main arteries, housing and urban functions. Notwithstanding a considerable lack of data, the gravity of the situation in Belgium is clear : since 1929, the amount of urbanized area has more than doubled, and, in 1970, the proportion of national territory which was urbanized (28 %) was far higher than in any of the neighbouring countries. It is therefore essential to control the use of land by means of a dynamic policy in country planning and development. The waste of land must be stopped by promoting the concentration of activities in specific centres, by keeping the majority of functions in the heart of the urban network, by assisting the use and re-use of available sites and by controlling any new developments, particularly housing schemes.