Background. Estimation of efficacy of antihistamines in patients with various severity levels and various clinical and laboratory variants of chronic idiopathic urticaria (CIU) . Methods. The retrospective study of the anamnestic clinical laboratory findings in 196 patients with CIU was performed. Results. The frequency of patients with full effect of antihistamines was 69%, partial efficacy — 11%, lack of efficacy — 20%. Lack of efficacy was dominated in patients with severe course of the disease and the presence of clinical manifestations of autoimmune disorders, non-specific inflammation and / or signs of cutaneous vasculitis. The full effect of antihistamines was dominated in patients with mild to medium CIU, with a normal clinical blood count and with a negative skin test with autologous serum. Conclusion. Lack of efficacy of of antihistamines in patients with severe course of disease, signs of autoimmune disorders specify on others nonhistamine mediators in CIU pathogenesis and application of the second and third line therapy of CIU.