The aim of this study was to analyze the effectiveness of the Epworth's sleepiness scale as a recourse aid in the diagnosis of the syndrome of obstructive sleep apnea. 475 patients attended this study, that sought the CESF to probable diagnosis of some sleep disorder. The data were collected from records, wich are of questionnaires, including the ESE, prepared by the CESF professionals and responded, previously, by the own patients. The study compared the result obtained in the scale of Epworth with the data of polysomnography. The analysis of data was performed using the SPSS, based on descriptive and inferential statistics, being used the average considering the standard deviation, and, to the crossing of variables, was used the chi-square test of Pearson, considering as significant statistically values of p<0.05. The results showed that gender, age and BMI are predisposing factors to SOSA.