Chronic obstructive pulmonary disease (COPD) characterized by irreversible airway obstruction, has numerous systemic complications including skeletal muscle dysfunction. Diaphragm, an important muscle of respiration, is also affected and it has far-reaching impact on morbidity. The study of diaphragm in individuals with COPD is challenging. Although the use of ultrasonography to study the function of diaphragm is in its nascent stage, it seems to be a promising tool for a comprehensive evaluation of diaphragm in COPD patients. This article reviews the available literature on the use of US in study of diaphragm on individuals with stable COPD.