The VNTR polymorphism of the PER3 gene is an individual variability arising from the primate genotype. It is associated with the expression of the circadian phenotype and sleep. In the case of human beings, they can influence our behavior, such as the chronotype. Regarding the circadian preference to perform daily activities. In addition, the environment in which the individual is inserted can often affect the time synchronization of biological and social clocks. Especially if we consider that we are increasingly deregulating sleep schedules due to demands for work, school or other factors. Social jet-lag is one of these irregularities in sleep patterns, this being between weekdays and weekends. Another factor that comes from the external environment and that can also influence sleep patterns is the territory in which the subject resides. Considering that latitude is a set of characteristics that involve geophysical and climatic factors, it seems to be related to sleep markers. Thus, the objective of this work is to verify which interactions exist between the V3TR polymorphism of the PER3 gene and specific environmental markers of latitudes in sleep parameters of young adults living along the latitudinal axis of the Brazilian territory. The method that was used consists of three stages, Stage 1 referring to the use of the sociodemographic questionnaire, the Munich chronotype and the excessive daytime sleepiness scale. Stage 2 was genotyping, where oral samples were taken and, subsequently, DNA extraction and classification of subjects from the VNTR polymorphism of the PER3 gene occurred. The third and current stage concerns the collection of variables related to latitude in three different cities with different latitudes: Maceió - AL, Campinas - SP and Porto Alegre - RS. The NOAA and INMET / BDMEP platforms will be used. The sample number is 762 participants. The inclusion criteria consider that these are undergraduate or graduate students who start classes between 7: 30-8: 00 am. The exclusion criteria consider the use of drugs that affect sleep and trans-regional travel in the month prior to the selection. It is expected to find possible associations between latitude, sleep parameters and individual variability regarding the PER3 gene polymorphism influencing sleep markers, such as social jet-lag, daytime sleepiness and sleep duration.