Abstract : Monitoring of the Southern bight of the north sea (Belgian Continental Shelf; BCS) and the Western Scheldt estuary for international purposes : Oslo and Paris Commission (Paris Convention 1992), the Joint Assessment Monitoring Programme (JAMP) and national purposes : possible harmful effects of sand extraction, dredging, Ö The BCS-programme concerns the chemical monitoring of te following components in sediment, suspended organic matter, invertebrates and/or fish : heavy metals, polychlorinated biphenyls (PCBs), organochlorinated pesticides (OCPs), polyaromatic hydrocarbons (PAKs) and volatile organic compounds (VOCs). The sediment is additionally analysed on water and carbon contents, organic matter, grain size, silt content and bacterial loads. The latter parameter and some abiotic factors are also analysed in the water column. The biological programme on the BCS is composed of the monitoring of the macrobenthos in sediment, epibenthos, fish diseases, biochemical stress indicators, detection of phatogens in flatfish blood and analyses of toxic algae in te water column. The monitoring programme in the scheldt estuary is restricted to chemical analyses of the sediment.