Three groups of chamois (Rupicapra pyrenaica) and three groups of Spanish ibex (Capra pyrenaica) were established to study the effects of sarcoptic mange on serum proteins and immunoglobulin G (IgG) levels. The first group of chamois consisted of 22 healthy Pyrenean chamois (R. pyrenaica pyrenaica) from a non-infested area, the second group consisted of 20 healthy Cantabrian chamois (R. p. parva) from an area where sarcoptic mange has been reported since 1994 and the third group consisted of 16 Cantabrian chamois from the same area but naturally infested by Sarcoptes scabiei. The first group of Spanish ibex was 39 healthy animals from a sarcoptic mange non-infested area, the second group was 23 healthy animals from a sarcoptic mange infested area and the third group consisted of 20 animals from the same area but naturally infested with the parasite. Blood samples were taken after killing the animals as part of hunting programmes. Values for total proteins, gamma-globulin and IgG were higher in infested and healthy chamois from the infested area compared to healthy chamois from the non-infested area, and IgG levels were higher in infested chamois compared to healthy-exposed chamois. Values for alpha2-globulin were higher in healthy Cantabrian chamois. In Spanish ibex, albumin, alpha2-globulin and IgG levels were lower in the healthy Spanish ibex from the non-infested area than in healthy animals from an infested area. The differences found in the chamois were indicative of the establishment of a humoral antibody response in the animals in contact with the disease. As the IgG levels were not significantly different between healthy and infested Spanish ibex from the same area, a different pattern of chronic infection with humoral response to the disease was suggested.