Abstract
Background and aims: Considering the importance of the related factors in learning and in the light of the fact that there was no study of this kind on dentistry students, so this research has been carried out in 2016 to evaluate the relationship between morning & evening patterns with the learning levels of dentistry students of Dentistry Faculty, Tehran Medical sciences, Islamic Azad University.
Material & Methods: in this descriptive study, first, the students were undergo morningness-eveningness pattern by Horn-Oostberg method. Then, the relationship between students’s learning level and the results of both end-of-session and end-term tests was evaluated by a linear regression test.
Results: In this study, 69 dentistry students were participated. 22 persons (31.88%) had an overnight sleep pattern, 28 persons (40.57%) intermediate, and 19 persons (27.53%) in the morning. in both tests, there was a significant correlation between the morningness-eveningness pattern and the learning level. End-of-session test with (P <0.004) and end-term test with (P <0.002) Besides, There was not any significant correlation between age and sex of participants and their level of learning (P = 0.45, 0.10) in both tests. 
Conclusion: It seems, The morningness -eveningness pattern of the students analyzed in this study was significantly correlated with their learning outcomes, that is to say that students who had morningness pattern had higher scores than midway ones and these ones had better scores compared to the eveningness ones.