Background:Chronic obstructive pulmonary disease (COPD) is characterized by obstruction in airflow; however, COPD is a systemic illness. Neurophysiological alterations, such as nerve conduction (monosynaptic reflex test) and strength, have been correlated with smoking, the severity of the disease, hypoxemia, age, hypercapnia and peak expiratory flow. In this study, we aimed to evaluate the peripheral nervous system (PNS) with electromyography (EMG) method in patients with COPD and to examine their relationship with each other