Chronic obstructive pulmonary disease is a prevalent pathology, which continues to increase with the longevity of the population and the increase in smoking prevalence. In Algeria, there is very little data on its prevalence and in particular on its evolution over time. long term. The objective of our work is to evaluate the functional profile of COPD patients in the wilaya of Sidi Bel Abbes. This is a prospective and observational study of a cohort of one hundred and thirty-five patients, followed over a 3-year period from January 2011 to March 2014. The most common functional profile of our population is represented by moderate-stage COPD (63.7%). COPD affects adults over 60 years of age with a clear male predominance. The important fact of our study is that this pathology is the prerogative of smokers. Smoking is found in 97% as a risk factor. This data highlights the importance of tobacco control as primary prevention in order to reduce the incidence of COPD.