Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease characterized by the destruction of biliary epithelial cells, presumably by autoimmune mechanism(s). Although lymphocytes play a pivotal role in the pathogenesis of PBC, the possible involvement of eosinophils has also been suggested. Recent studies have shown that eosinophilia possibly occurs in the peripheral blood of PBC patients. We present four cases of asymptomatic middle-aged women with moderate-to-high eosinophilia observed during random investigation. Alkaline phosphatase (ALP) was increased in two of them. As a result of clinical and laboratory evaluations the early stages of PBC were diagnosed in all the patients, as attested by the detection of high titres of anti-mitochondrial antibodies and the characteristic lesions on liver biopsies. Liver function tests and eosinophils returned within normal limits after 2 months of treatment with ursodeoxycholic acid, suggesting that its potential immunomodulatory actions may extend to eosinophils. Our report further supports the possibility that eosinophilia may occur in PBC, especially in its early stages. From the clinical point of view, we believe that PBC should be considered in the differential diagnosis of eosinophilia with an otherwise unknown origin. In particular, PBC should be suspected in a patient when other causes of eosinophilia have been excluded, irrespective of the presence or absence of symptoms, or the presence or absence of elevated ALP. In such cases further evaluation for anti-mitochondrial antibodies should be done. These observations might assist the development of future therapeutic concepts in the management of PBC, at least for patients in early stages of the disease.