A serodiagnostic test (ELISA) for detecting antibodies to Sarcoptes scabiei in the sera of pigs was evaluated. The ELISA results from 221 specific pathogen‐free pigs of three different age categories were used to establish a cut‐off value for the assay. Background optical density values differed significantly between the three groups, the sows having the highest values. The mean + 3 sd of their values was chosen as the cut‐off. Four farrow‐to‐finish herds of pigs with sarcoptic mange were investigated. Skin scrapings were taken from each animal for the demonstration of S scabiei and their sera were assayed for the presence of antibodies to the mite. All the herds had active infections with S scabiei and antibodies to S scabiei were found in a significant number of the animals sampled. The sensitivity and specificity of the ELISA were 87.8 and 99.5 per cent, respectively, employing clinical diagnosis as the gold standard. A higher sensitivity (100 per cent), but a lower specificity (32.8 per cent) was obtained when the results of skin scrapings were used as the gold standard.