Tehran University of Medical Sciences Journal of Sleep Sciences 2476-2938 1 2 2016 07 27 67 73 EN Abolfazl Mozafari Department of Medical Sciences, Qom Branch, Islamic Azad University, Qom, Iran Maryam Tabaraie Department of Medical Sciences, Qom Branch, Islamic Azad University, Qom, Iran Mohammad Hossein Mohammadi Tahrodi Department of Medical Sciences, Qom Branch, Islamic Azad University, Qom, Iran 2016 06 18 2016 06 18 Background and Objective: Morningness–eveningness (ME) refers to the individual differences in diurnal inclination, sleep-wake pattern for activity, and vigilance in the morning and evening. Quantitative and qualitative components of sleep can be measured through its quality. This study aimed to evaluate the association of ME chronotype with sleep quality and insomnia in students. Materials and Methods: This cross-sectional study was performed from September 2013 to July 2014 among students. A total of 400 students of Islamic Azad University of Qom in the 1st to 4th year of education were recruited in this study. The students filled out questionnaires including demographic characteristics, Pittsburgh Sleep Quality Index (PSQI), and Insomnia Severity Index (ISI) and a self-assessment questionnaire for ME. Data analysis was performed using SPSS version 18 and simple and multiple linear regressions were used to quantify association between ME types with ISI and PSQI scores. Results: A mean age of participants was 24.01 ± 5.80 years. A total of 164 (41%) of participants were male. Of these, 38.5% were in eveningness, 34.3% in intermediate and 27.3% were in moriningness chronotype groups. A significant association was observed between morningness chronotype and poor sleep quality (P < 0.001), but the relationship with insomnia was not statistically significant (P = 0.080). Conclusion: This study showed morningness chronotypes are more likely to have poor sleep quality. https://jss.tums.ac.ir/index.php/jss/article/view/31 https://jss.tums.ac.ir/index.php/jss/article/download/31/27