OBJECTIVES: COPD is a chronic disease that causes disability and increases with age. The aim was to assess the quality of life of COPD patient treated in Primary Assistance in Spain. METHODS: It is an epidemiological, observational, cross-sectional and descriptive study. There were included mild or severe COPD patients (according to FEV1 value). There were collected demographic, clinical and comorbidity data. The patients were asked to fill the MOS SF-12 questionnaire. RESULTS: A total of 10,711 patients were collected [75.6% were male, 53.4% had moderate COPD (FEV1: 40-59%), 18.9% were active smokers and 21.8% were obese (CMI >/= 30)], with a mean age of 67.1 + 9.6 years and a COPD time evolution period of 10.4 + 7.3 years. The 14.6% of the patients answered that their health was bad and 55.4% could not make the diary life activities because of their disease. Country normalized physical (PCS) and mental health (MCS) component summary scores (SF-12) indicated significant impairment in both domains compared to the general Spanish population: PCS; 36.0+9.9 vs. 50.1+9.5, and MCS; 48.3+10.9 vs. 50.0+9.6, respectively. PCS deteriorated independently with both age and severity of COPD, (p<0.0001 in all cases), but no differences were seen by smoking habit after adjusting by age, sex and severity. PCS also deteriorated with number of hospitalizations and exacerbations (p<0.0001), and in obese subjects (p<0.0001). As expected, MCS deteriorated slightly with age (p<0.01), but no differences were seen according to severity of disease. After adjusting, non smoker and ex-smokers showed better MCS than active smokers (p<0.05). MCS also deteriorated with number of hospitalizations and exacerbations (p<0.001). CONCLUSIONS: COPD decreases patients’ physical and mental components of QoL, while increasing level of disability in Spain. The impairment in QoL increases with age, severity and exacerbations of COPD.