Chronic obstructive pulmonary disease is an inflammatory disease of the lung caused in most cases by harmful particles from tobacco smoke. The morbidity and mortality of COPD are on the rise. Assessment of disease severity and approach to treatment have experienced changes in the last two decades. GOLD guidelines in 2001, and revision of guidelines that followed up to 2011, classified COPD based on value of FEV1 to mild, moderate, severe and very severe. The guidelines were amended significantly in 2011 and to assess the severity of the disease, severity of obstruction or FEV1, the intensity of symptoms and the number of exacerbations in the previous year were used. At this point GOLD guidelines recognize two clearly defined fenotypes - frequent exacerbator and ACOS. Future approach to the treatment of patients with COPD involves phenotypic approach to COPD according to clinical characteristics of the patient, which are not yet fully defined. For this purpose, a lot of studies that have been conducted, attempted to define which parameters should be considered in determining the phenotypes. This phenotypic approach in the classification of patients with COPD, which is expected, will enable more effective, targeted, personalized therapeutic approach to patients.