The Epworth Sleepiness Scale (ESS) has been reputed as a quick, valid, and reliable method to assess Daytime sleepiness (DS). Since its publication, it has been translated into a number of languages. Our aim was to determine validity and reliability indicators of an Spanish language version ESS for Mexican population. Considering that in developing countries the majority of persons use public transportation, validity and reliability indicators were also assessed utilizing the ESS without item 8. ESS was applied to a Group of college students (GCS), a selected group of Healthy subjects (HS), and a Group of patients with Sleep disorders (GPSD). We made an ESS comparison among the 3 groups, calculated the correlation between the ESS and the Multiple Sleep Latency Test (MSLT) and determined construct validity and internal consistency. GCS and GHS had lower ESS scores than GPSD. Regarding convergence validity, we obtained a negative correlation between the ESS and the MSLT; we also found a rise in the ESS score associated with an increase in the Apnea- hypopnea index (AHI). With respect to construct validity (employing main component analysis and varimax rotation), we found that one factor explains 52.01% of variance. We determined that the ESS internal consistency was 0.85. When item eight was suppressed, validity and reliability remained acceptable. The present ESS Spanish-language exhibited suitable levels of validity and reliability. Use of the ESS, suppressing item eight, allows assessment of DS more accurately in individuals who do not travel by automobile on a regular basis.