The Netherlands participates in the Joint Assessment and Monitoring Programme (JAMP) of the Oslo and Paris Commissions. This report presents the results of the Dutch contribution to the programme 2001 and the sediment results of 2000 which were not yet available at the time of the last evaluation report of the Netherlands in 2000 (ref.19). Tributyltin (TBT) in water from inland marinas has been monitored ever since 1990. From the resultant data it is clear that there has been a decrease in TBT since the ban on the use of TBT on vessels less than 25 metres in length. Recent data on TBT from the monitoring of sediment indicate relatively high concentrations of TBT and triphenyltin (TPhT) in all Dutch marine waters. TBT concentrations measured range between 3 and 212 ?g TBT/kg sediment normalised to 5% organic Carbon. This implies that the Dutch target value MTR (Maximum Tolerable Risk concentration) of 0.7 ?g/kg, laid down in the Fourth National Policy Document on Water Management is being exceeded by a factor 4.5-300. The highest TPhT concentration was about 50 ?g TPhT/kg sediment normalised to 5% organic Carbon, the lowest values were below the detection limit (