Methods of collecting, analysing and presenting data on the diets of seabirds are reviewed, with consideration of methods employed in diet studies of other organisms. Killing of birds continues to be the primary source of dietary information from birds at sea but is no longer necessary for studies on land. Stomach pumps obtain complete stomach evacuation with low mortality. Stomach samples should be examined as soon as possible after collection, to avoid biases caused by preservation. Presentation of data is best done by rank-order to facilitate comparison between studies, but as many data should be provided as possible. Future work on diets will be strengthened through knowledge of digestion rates and nutritional values of food