en General پژوهشي Research Article Background: Population aging is a major health issue in most countries. Sleep is one of the significant factors affecting aging and elderly people&rsquo;s quality of life. The present study was done to assess sleep quality and its contributing factors among elderly people. Methods: This cross-sectional descriptive-analytical study was conducted in 2016 on 284 elderly people aged sixty or more. Participants were selected from healthcare centers located in Birjand city, Iran, via the two-stage cluster sampling method. Data collection tools were a demographic questionnaire and the eighteen-item pittsburg sleep quality index. The collected data were entered into SPSS software (v. 16.0) and analyzed using Mann-Whitney U and Kruskal-Wallis tests at the significance level of less than 0.05. Results: Participants were mostly female (59.3%) and aged 68.93 &plusmn; 8.44 on average. Around 69% of them had good sleep quality. The majority of them had mild problems in subjective sleep quality (66.2%), sleep latency (40.5%), and sleep disturbances (64.8%), no problem in sleep duration (58.1%) and sleep efficiency (64.2%), no daytime dysfunction (71.5%), and most of them did not use sleeping medications (79.3%). Sleep quality had significant relationships with gender (P = 0.03), pain (P = 0.007), exposure to environmental stimuli (P < 0.001), regular physical activity (P = 0.008), and menopause-related problems (P = 0.03). Conclusions: Elderly people in Birjand, Iran, have a relatively good sleep quality. The most important factors contributing to their sleep quality are gender, pain, exposure to environmental stimuli, regular physical activity, and menopause-related problems. Empowerment of healthcare providers regarding the accurate diagnosis and effective management of elderly people&rsquo;s sleep disorders is recommended. Aging,Sleep Quality,Sleep Problem,Daily Function 0 0 http://mcj.bums.ac.ir/browse.php?a_code=A-10-1-54&slc_lang=en&sid=1 Samaneh Aliabadi 10031947532846003519 10031947532846003519 No MSc of Rehabilitation Management, Social Determinants of Health Research Center, Birjand University of Medical Sciences, Birjand, Iran Mitra Moodi 10031947532846003520 10031947532846003520 Yes Mitra Moodi, Associate Professor of Health Education and Health Promotion, Social Determinants of Health Research Center, Birjand University of Medical Sciences, Birjand, Iran. Tel: +98-5632381251, E-mail: mitra_m2561@yahoo.com Mohammad Reza Miri 10031947532846003521 10031947532846003521 No Associate Professor of Health Education and Health Promotion, Social Determinants of Health Research Center, Birjand University of Medical Sciences, Birjand, Iran Zoya Tahergorabi 10031947532846003522 10031947532846003522 No Assistant Professor of Phisiology, Medical Toxicology and Drug Abuse Research Center (MTDRC), Birjand University of Medical Sciences, Birjand, Iran Roghayeh Mohammadi 10031947532846003523 10031947532846003523 No Assistant Professor of Physiotherapy, Neural Muscle Rehabilitation Research Center, Rehabilitation School, Semnan University of Medical Sciences, Semnan, Iran