<b>Background:</b> It has been reported that patients with ACOS have more symptoms, higher exacerbation rate, more comorbidities, worse quality of life and higher health-care costs than patients with only asthma or COPD. <b>Objectives:</b> To measure the prevalence of asthma, COPD and ACOS in primary-care patients from PUMA study, and evaluate the association between exacerbations and hospitalizations for exacerbations in ACOS patients. <b>Methods:</b> Subjects were classified in three groups: COPD (post-BD FEV₁/FVC&lt;0.70); Asthma (presence of wheezing in the last-year + reversibility (post-BD FEV₁ and/or FVC &gt;12% and &gt;200mL); ACOS the combination. <b>Results:</b> 1,743 individuals were interviewed, 1,540 performed spirometry, 274 had only COPD (FEV₁/FVC&lt;0.70 post-BD), 43 only asthma (reversibility + wheezing), and 35 ACOS. <b>Conclusions:</b> Patients with ACOS seem to have a higher risk for exacerbations (2.2 times more than the COPD group).