Objective: to assess sleep habits and sleep quality perception in a Colombian and Mexican youthsample. Materials and methods: following a sleep diary methodology with a questionnaire of 27categorical and quantitative items, the assessment was done immediately upon awakening. Results:it was applied to 317 high school (n= 189) and undergrads (n= 128) in Bogotá, Colombia (n= 197)and México City, México (n= 120); 147 females (46,4%) and 170 males (53,6%). The mean agewas 18,6 ± 2,81 years with a median and mode of 17 years. The Cronbach’s alpha obtained from135 measurements during the study period was 0,86 and 0,57 from the mean values of 27 scaleitems. An inverse correlation was found between hours of sleep per night and number of naps (r=-0,12; p= 0,029); 38% of participants did not nap and slept on average 7,6 night hours or more(X2= 2,78; p= 0,047). The men took more naps than women (men 76,5%; women 55,6%; X2=15,26; p= 0,000). A reduction of hours of sleep per night and the need for naps was significantlyassociated with participants’ gender. The mean and median hours of sleep per night (7,2 hours)was used to classify the population into two groups: sleep (+) 7,3 or more hours and sleep (-) 7,2hours or less. These groups were compared. Conclusions: youth population evaluated showed areduction of hours of sleep per night. This was associated to naps frequency and participant gender
