Objective. To study respiratory burst activity in neutrophilic granulocytes in the onset of Graves’ disease (GD). Material and methods. Twenty-six females aged 18—55 years (mean age, 40.7±13.2 years), with the diagnosis of Graves’ disease verified for the first time, were enrolled in this study. Spontaneous and zymosan-induced chemiluminescence (CL) was assessed using a CL3606 36-channel analyzer for 90 min. The following parameters of the chemiluminescence curve were determined: time to attain the maximum (Tmax), the maximum intensity (Imax), and the area under the curve (S). Results. Patients with GD and lucigenin-dependent CL of neutrophils exhibited decreased zymosan-induced CL and the increased Imax of luminol-dependent spontaneous and zymosan-induced CL of neutrophils. Association between the anti-TPO level in blood serum with Tmax (r=–0,70; р=0.036) and Imax of luminol-dependent induced CL (r=–0.72; р=0.030) was found. The maximum level of synthesis of secondary reactive oxygen species (ROS) was found to be elevated in patients with GP both at relative rest and upon antigen-induced respiratory burst. Conclusion. In patients with GD, respiratory burst activity in neutrophils increases due to synthesis of secondary reactive oxygen species. Upon the onset of GD, already at the stage of subclinical thyrotoxicosis, the association between the indices of respiratory burst in neutrophils and thyroid hormones is lost but there emerges a relationship between the CL response and anti-TPO concentration,