The Netherlands participates in the Joint Assessment and Monitoring Programme (JAMP) of the Oslo and Paris Commissions. In this framework it was agreed that all members or contracting parties should report on the national comments that accompany the data submissions to ICES database. This report presents the results and comments of the Dutch contribution to the JAMP programme 2004. Wintertime nutrient concentrations of DIN (Dissolved Inorganic Nitrogen) and Ortho-phosphate were in agreement with earlier reported downward trends. Though both nutrients still exceed their respective MTR (Maximum Tolerable Risk concentration), the downward trend over the last 10 years seems more progressive for Ortho-phosphate than for DIN. In general in water, all measured dissolved metal concentrations were smaller than the MTR levels. However, at brackish water location in river Meuse outlet and at a transitional water location in the Western Scheldt copper occasionally exceeded the MTR. Also zinc peaked at times in the Meuse outlet reaching concentrations above the MTR. The measured metal concentrations in sediment showed all to be below the MTR. However for the Western Scheldt As, CD, Cr, Cu, Hg, Pb and Zn and for the Eastern Scheldt As, Cr, Hg, Ni, Pb and Zn occasionally reached concentrations above the VR. The assessment of ?-HCH in water? presented here confirmed the earlier findings and showed a strong decreasing trend in concentrations up to levels well below the VR. Although the earlier reported decreasing trends (enkelvoud?) in TBT concentrations in water continued (not treated here) TBT concentrations in sediment still exceeded the MTR (set at 0.7 ?g Sn/kg) by a factor of 24 to 100. A general improvement in flounder health, in terms of lymphocystis, skin ulcers and liver tumours, was noted for the Wadden sea, Eastern Scheldt and coastal zone since the early nineties. An overview is given of the quality assurance Programme of the Dutch Laboratories and details on detection limits, and participation in QUASIMEME and BEQUALM exercises.