Background: Chronic obstructive pulmonary disease (COPD) is a common disease associated with premature death. Tobacco exposure is the main risk factor, but lower socioeconomic status, early life insults, and occupational exposures are also important risk factors. Socially marginalized people, facing homelessness, substance use disorder, and mental illness, are likely to have a higher risk of developing COPD, and, furthermore, experience barriers to healthcare access and consequently poorer outcomes. Objective: This study aims to assess COPD prevalence and the impact of opportunistic screening among hospitalized patients who are in contact with hospital social nurses. These patients constitute a group of patients with a high prevalence of psychiatric and somatic diseases, substance use, low life expectancy, and are socially marginalized. Methods: The present prospective longitudinal study includes a clinical examination at baseline. Participants will have spirometry done and be interviewed regarding risk factors, socioeconomic conditions, and respiratory symptoms. The 5-year follow-up assessment incorporates data from baseline and register data over the 5 years, including information on morbidity, use of COPD medication, hospital contacts, mortality, and socioeconomic factors. Anticipated results: Referral for further diagnostic work-up and management after the screening, including COPD treatment and smoking cessation support, is expected to improve survival rates. The study is still enrolling patients. Trial registration: The study is registered at ClinicalTrials.gov, NCT04754308 with study status: “enrolling”.