INTRODUCTION: Self-assessment questionnaires, can provide subjective data about the intensity of daytime sleepiness. Among the existing questionnaires the most used one is the Epworth Sleepiness scale (ESS), which measures the propensity to fall asleep, as well as the severity of excessive sleepiness, [5] and the evaluation of the response in OSA treatment. In 1997, the Functional Outcome Sleep Questionnaire (FOSQ), was developed to evaluate the functional impact of sleepiness in daily life activities [6]. In this study, we will use the Epworth sleepiness scale, and the Functional Outcome Sleep Questionnaire in its shortest version, known as FOSQ 10[7], developed in 2009 by Weaver, who in addition to drowsiness included the relationship of sleep to the quality of life. MATERIALS AND METHODS: The following variables were analyzed: age, anthropometric characteristics (weight, height, body mass index [BMI]), duration of complaints, type of complaints related to sleep (snoring, insomnia, excessive daytime sleepiness), sleep apnea and hypopnea index (AHI). Inclusion criteria were patients between 18 and 80 years, without prior surgery, with complaints related to sleep disorders. Exclusion criteria were: children under 18 years, previous surgeries, previous use of CPAP. RESULTS: the significance level at 5%, where we observed moderate and significant inverse correlation between FOSQ and ESS (p < 0.001), which evidences that the higher the ESS value, the lower the FOSQ value will be CONCLUSION: This study has shown an acceptable correlation between the scores on the Epworth and FOSQ scale