This chapter reports the concentration levels and occurrence of organic chemicals dissolved in surface water of the Danube River.The scope of the campaign was the screening of trace organic contaminants in the water column of the Danube, the assessment of their spatial distribution along the river, evaluation of their temporal trends (demonstration at a single site JDS4-15), and comparison of levels of selected hydrophobic organic pollutants in surface water and fish. The sampling was performed using stationary passive samplers deployed for 100 days at nine sites close to sites where fish were also caught for analysis. Passive samplers provide a time-integrated image of pollution in the aqueous phase over an extended time period, providing a representative picture of the surface water quality in summer 2019. The results show that the spatial variability of investigated hydrophobic priority substances in surface water of the Danubeislow. No deterioration of Danube surface water contamination by hydrophobic priority substances was observed in JDS4 in comparison with the results from JDS3. Among investigated organochlorine compounds and PAHs at JDS4-15, a significant concentration decreasing trend was observed for hexachlorobenzene, PCB 28, PCB 52 and p,p-DDE, whereas no significant temporal trend was found for PCBs with a higher degree of chlorination or for priority PAHs. Passive sampling of hydrophobic substances in surface water provides a worst-case scenario of fish exposure to those substances and should be considered as a viable alternative to biota monitoring. In the Upper and Middle Danube stretches, the occurrence of polar organic contaminants is associated with the discharge of municipal wastewaters to the river. In the Danube stretch downstream of the Iron Gates dam, the contaminant pattern and concentrations in surface water reveals application of pesticides in agriculture as the main contamination source.