Introduction: Chronic obstructive pulmonary disease (COPD) is a permanent narrowing of the airways caused by emphysema or chronic bronchitis. Based on previous research, it has been established that the disease affects physical and mental health and significantly reduces the quality of life. Aim: The aim of this research is to examine the connection between certain aspects of the quality of life and the expression of negative emotional states: depression, anxiety and stress in people suffering from COPD in the pulmonology clinic of the General Hospital "Dr. Ivo Pedišić" Sisak. Methods: An observational-cross-sectional study was conducted using the survey method in direct contact. Respondents filled out an anonymous survey in paper form with preliminary explanations and instructions about participation in the research. Results: 128 respondents who are treated in the pulmonology clinic of the General Hospital "dr. Ivo Pedišić" Sisak. Data analysis showed that there are significant associations (r= 0,829; p<0,01) between reduced quality of life and health and negative emotional states (stress, anxiety and depression). It was established that the reduced quality of life and the appearance of negative emotional states depend on the age of the subjects, but also to a greater extent on the duration of the disease. The connection between the reduced quality of life and the appearance of negative emotional states with regard to the family status of the respondents has not been proven. Conclusion: The proven reduced quality of life related to health and the occurrence of negative emotional states in patients with COPD represent a significant problem in the patient's life and health care. In the treatment of patients with COPD, in addition to assessing the physical condition, attention should also be paid to the assessment of the psychological condition, and experts from other scientific fields should also be included in the treatment process in view of the assessed status.