The marine mammals catch rate of pelagic trawling in the North-east Atlantic has not previously been assessed by direct observation. A study was funded by the European Commission to collect information on the catches of fish and mammals by several pelagic trawl fisheries from England, France, Ireland and Netherlands. This paper presents a summary of the results, as far as the by catch of marine mammals is concerned, between 1994-1995. It was not possible to carry out observations of all the pelagic trawl fisheries but a total of eleven fisheries were investigated in this study. In one fishery (Irish herring (Thunnus) trawling), four grey seals (Phoca vitulina) were caught in separate trawls during slightly more than 100 hours trawling. Cetaceans (dolphins) were incidentally caught in four pelagic fisheries (Dutch horsemackerel, (Trachurus trachurus) French tuna, (Thunnus) French hake, (Merluccius) French sea bass trawling Dicentrachus labrax). Eleven different trawls caught a total of eighteen dolphins (Stenella). These catches were observed during 1300 hours of deployment of the trawls. Visual inspection of pelagic trawl emptied using fish pumps was thought to be unreliable for the detection of cetacean bycatch. The extent of observation and number of observed bycatches is however too small to make a reliable assessment of overall by catch rates. In those fisheries where cetacean bycatch occurred rates were between 1.1 and 1.5 cetaceans per 100 hours of trawling.