During the MARSEN 79 experiment, attenuation of capillary and gravity water waves by two oleyl alcohol and one methyl oleate surface films (''slicks'') was investigated. A slight influence of an oleyl alcohol slick occurs at frequencies between 0.5 Hz and 0.7 Hz and 0.7 Hz and above 0.7 Hz (wavelength L=3.2 m) wave attenuation becomes significant. A methyl oleate slick causes only a slight wave damping in the frequency range f6.7 cm). In the capillary wave range f≥14 Hz the wave-damping characteristics for the two surface film substances are comparable. In the high-frequency capillary wave range f>20 Hz, however, methyl oleate surface films act more strongly on the wave field, as was demonstrated by additional wind-wave tunnel experiments. The different wave attenuation characteristics of these two surface active compounds are attributed to different interaction between their hydrophilic part and the adjacent water layer.