Abstract Antibodies against Fasciola hepatica were detected in sera from experimentally infected sheep and calves. Titres in sera from field-infected sheep were related to fluke burdens. Indirect haemagglutination, counter-immunoelectrophoresis and double immunodiffusion were compared. Indirect haemagglutination and counter-immunoelectrophoresis were superior to double immunodiffusion and positive reactions in these techniques preceded the presence of parasite eggs in the faeces by at least 50 days. The relative advantages of the immunological techniques are discussed.