Spray-dried animal plasma (SDAP)is frequently used as an ingredient of weanling piglets diets in order to improve feed intake and to reduce post-weaning diarrhoea. It is concluded that dietary SDAP levels up to 6 % raise both average daily gain (ADG) and feed intake (ADFI) in the first two weeks after weaning in a dose-dependent fashion. SDAP also reduces feed conversion ratio (FCR). Multiple regression analysis indicated that, apart from SDAP dose, baseline growth rate is an important determinant of the effect of SDAP on ADG, with high baseline growth rate being associated with small effects of SDAP. Porcine plasma has more beneficial effects than bovine plasma. Possible modes of action are discussed. It is suggested that, in addition to improving feed palatability, SDAP reduces post-weaning intestinal disease by preventing attachment of pathogens.