Juvenile dermatomyositis (JDM) is the most common chronic idiopathic inflammatory myopathy in children. The characteristic symptoms of this disease are: muscle weakness concerning mostly the shoulder and pelvic girdles and dermatosis manifested as face oedema, heliotrope rash of eyelids, erythema and exfoliation on the skin of the face and chest. Increased indicators of the “acute phase”, high activity of muscle enzymes (transaminase, creatine kinase and lactate dehydrogenase) and sometimes the presence of antibodies against Jo-1 are typical of laboratory blood tests in JDM. The electromyography test demonstrates primary damage of muscles; inflammatory infiltrations are found in histopathology evaluation of dermatomyositis specimen. Calcium deposits in soft tissues leading to muscle atrophy and joint contractures are commonly observed in children. The first line treatment in patients with JDM is based on corticosteroids, if they are ineffective, the immunosuppressive or biological drugs including immunoglobulins are being used. In this paper we presented a patient with severe JDM complicated with calcinosis, taking into account clinical symptoms of the disease and possible methods of treatment. We also discussed the difficulties with the choice of the most effective pharmacological treatment for this patient. In the case of this patient, who is now a 14-year-old boy, general dermatosis and rapidly increasing numerous calcium deposits in the skin, subcutaneous tissue, fascia and muscles, which appeared three years after the time of displaying of the first symptoms, were observed (Fig. 1-8). Due to the severe course of the disease, an aggressive conventional therapy was introduced (corticosteroids, methotrexate, cyclosporine, pamidronate), which did not give satisfactory results of treatment and improvement of the child’s clinical condition. On the basis of reports taken from the international literature, it was decided to implement the biological treatment with the use of anti-TNF (infliximab). However, the result of the treatment was unsatisfactory. It was only the use of a therapy based on intravenous injection of immunoglobulins that brought good therapeutic effect (Table I).