Introduction. The circadian rhythms represent endogenously generated rhythms of 24-25 hours ensuring the cyclicity of physiologic and behavioral processes within the body. Their study value resides in a better understanding of the homeostatic activity of the organism as well as how their disturbances induce diverse pathogenetic pathways affecting various systems. A wider knowledge about how everything in our body is synchronized, will ensure us with more efficient treatment schemes and the development of chrono-pharmacotherapy. Aim of the study. The purpose of this study is to highlight the significance of respecting the circadian rhythms by evaluating the circadian component of the sleep-wake cycle and its impact on the physical and psychological state of first year medical students at the end of the study year. Materials and methods. At the end of the study year 2018-2019, 55 students from the Faculty of Medicine N°1 of the Nicolae Testemitanu State University of Medicine and Pharmacy filled a self-administered questionnaire, which included a general data section and four tests: Pittsburgh Sleep Quality Index, Beck, Hamilton and Dijon. These tests helped in assessing their lifestyle particularities, sleep quality as well as degree of anxiety, depression and physical development. Results. Among the participants, 11 out of 19 students that use to go to sleep before 00:00 got a PSQI<5, only 13 out of 36 registering a PSQI>5. Those registering a Hamilton score higher than 4 tended to sleep fewer hours scattered other a day (P=0,001). On the other hand, a less depressive state (<9 on Beck scale) was observed in students having an irregular sleep pattern other 24 hours (P=0,0009). Dijon test-based results suggest a higher degree of physical development if they used to get to sleep after midnight. Conclusions. The study proves disorganized lifestyles modifying the circadian rhythms induce over time alterations in homeostasis affecting both physical and mental state. In order to ensure higher life quality standards and better medical practice, regulated daily habits according the biological rhythms are encouraged.