Aim of this research has been to create a method to detect sIgE to thyroid peroxidase (TPO) in serum of the patients with autoimmune and allergic diseases.Materials and methods. In this research native affine-purified TPO (more the 95% clean, enzyme activity 60±15 of enzyme unit per mg) with immune dominant elements only (confirmed by inhibitory ELISA) has been used. The detection of sIgE in serum, combined with TPO, was carried out with monoclonal antibodies to IgE (8E/4F4) conjugated with horseradish peroxidase.Results. In serum of patients with bronchial asthma, allergic rhinitis and chronic spontaneous urticarial sIgE to TPO has been detected in 18—21% of cases. The healthy people and the patients with autoimmune thyroiditis had no sign of sIgE to TPO in their serum.Conclusion. The detection of sIgE to TPO in cases of patients with chronic spontaneous urticarial and allergic diseases will make possible to perform the early diagnosis of thyroid autoimmune disorders and provide timely and adequate therapy.