Aims of study: This study was planed to evaluate the prevalence of OSA in COPD patients in compare to control subjects and its clinical characteristics. Subjects and methods: 60 smoking males, living in Dalat city had been induded and devided into 2 groups: control group (without COPD
N=30), COPD group (N=30). All subjects underwent clinical examinations, spirometry, and polysomnography, Pichot and Epworth scales. Results: Mean ages of study subjects were not different between 2 groups (54 + or - 12 vs 52 + or - 8). The prevalence of OSA in COPD was higher than control subject (23 percent vs 10 percent). The micro arousals and AHI in COPD were higher than control subjects (22 + or - 11 and 8 + or - 9 vs 8 + or - 5 and 5 + or - 6
P0,00l, P0,05). Nadir Sp02 in COPD patients was significantly lower than control subjects (86 + or - 9 percent vs 91 + or - 8 percent). The percentage of COPD patients having snoring at sleep, Sp02 90 percent and 85 percent were higher than control group. There were significant correlations between AHI with snoring at sleeps, nysturie, and Epworth scores (R