Introduction Thoracic Outlet Syndrome (TOS) is a group of conditions characterized by compression of the structures in the lower neck and upper chest area. On average 6.5 physicians of different specialities need 4.3 years to develop TOS diagnosis. Early detection of changes in conduction of nerve impulses may lead to more effective treatment of patients. Aim The aim of the study is to present the scheme of diagnostic tests of neurophysiology contributing to the objective diagnosis of TOS, as well as the positive results of tests in a group of sixteen patients with clinically confirmed pathological symptoms. Material and Methods In the study participated 16 patients with clinically diagnosed TOS and sixteen healthy people at the age from 18 to 36 as a control group. In both groups, tests were carried out in the field of bilateral clinical neurophysiological diagnostics. Results Compared to studies performed in a control group of healthy volunteers, 50% of patients with clinical symptoms of TOS confirmed abnormalities in the diagnostic tests of clinical neurophysiology, unilaterally or bilaterally. Conclusions In the diagnosis of TOS, sEMG recordings conducted from the distal muscles of the upper limbs in conditions of maximum contraction after induction of ischemia ("hand-raised test"), segmental examination of ENG nerve impulse conduction in motor fibers after stimulation of the median and ulnar nerves and MEP examination after supraspinal stimulation C5 and C6 are particularly useful. Confirmation of a relatively high percentage of positive TOS tests in patients requires a greater number of cases.