Introduction: Chronic obstructive pulmonary disease (COPD) is one of the most important public health problems due to its high prevalence, progressive nature, and costs of treatment and care. Material and methods: We enrolled 1026 patients in our study (86.3% of the registered patients) to assess the incidence and severity of COPD, the degree of underdiagnosis, the association with smoking, and the presence of co-morbidities. Results: COPD was diagnosed in 8.1% of the subjects over the age of 40, most of whom were current or former smokers (90.3%). More than half of the subjects (61.3%) presented with mild disease, 35.5% with moderate disease, and 3.2% with severe disease. The development of COPD is most affected by the number of pack-years and age. In women, the development of COPD is associated with a smaller number of pack-years. Conclusions: We found that COPD is underdiagnosed in the primary care setting, as only 1% of the subjects carried the correct diagnosis. One of the reasons why COPD goes underdiagnosed is that doctors do not perform spirometry often enough. Cardiovascular disease is significantly more prevalent in patients with COPD.