 Chronic obstructive lung disease COPD and pneumonia are leading causes of death in United States and worldwide. COPD, which is also a significant source of disability, is increasing in prevalence. Approximately 14 million adults have asthma, which leads to approximately 12 million missed work days per year in the United States. In adults, COPD and asthma often coexist. Treatment options for COPD are limited, and prevalence of vitamin D deficiency is high. COPD lung disease COPD, asthma, airflow obstruction, and most COPD additional co-morbidities responsible for COPD progression e.g., respiratory infectionspneumonia, muscle weakness, cardiac failure may benefit from vitamin D supplementation therapy, but this requires rigorous testing. Marine omega-3 fatty acids work through different pathways from vitamin D to affect inflammation. Observational studies and clinical trials suggest that consumption of fish andor fish oil may protect against COPD, asthma or pneumonia, but the data are not consistent. Thus, there is a compelling need for a clinical trial to evaluate the potential benefits or risks of vitamin D and fish oil supplementation on COPD and asthma exacerbations, airflow obstruction and decline of lung function, and risk of pneumonia. 