Tehran University of Medical Sciences Journal of Craniomaxillofacial Research 2345-5489 7 2 2020 10 03 76 83 Mohammad Hadi Nazari School of Dentistry, International Campus, Tehran University of Medical Sciences, Tehran, Iran AND Research Center for Caries Prevention, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran. Simin Zahra Mohebbi Research Center for Caries Prevention, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran AND Department of Community Oral Health, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran. Mohammad Javad Kharazifard Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran. 2020 09 07 2020 09 13 Objective: This study assesses the oral health knowledge, attitudes, care practices, and related underlying factors of people with diabetes. Materials and Methods: In a descriptive cross-sectional study using a random sampling method, 201 patients who referred to five comprehensive health centers in the South of Tehran, Iran, participated. A previously published questionnaire was used, and its reliability and validation analyses were performed. There were 31 Open-Ended, Closed-Ended, and Likert scale questions, including 26 on key underlying factors, one with 13 parts in oral health knowledge, one with nine parts related to oral health attitudes, and three on care practices. Data were entered into SPSS software version 24, and descriptive statistics and regression were used to analyze and report the results. Results: The mean age of participants was 49 years (σ=7.6), and males accounted for 58.2% of the study population. 37.48% of the patients had poor oral health knowledge, whereas 61.76% of them reported average care practices, with 68.29% above average attitudes. Among the study population, only 33.3% brushed more than once per day. 35.8% considered bleeding gums while brushing unacceptable, and 42.3% reported gums swelling and redness as signs of disease. Over half of respondents (52.2%) strongly supported the idea of keeping their natural teeth as long as possible, while 41.8% were only agreed. On the other hand, patients with a higher level of education scored better in knowledge, attitudes, and care practices (p-value<0.05). Conclusion: As the knowledge, care practices, and to some extent attitudes of people with diabetes toward their general oral health were unsatisfactory, an appropriate training program should be developed to warn diabetic patients of the importance of oral health and its two-way impact on diabetes. Keywords: Knowledge; Attitude; Practice; Oral health; Diabetes. https://jcr.tums.ac.ir/index.php/jcr/article/view/342 https://jcr.tums.ac.ir/index.php/jcr/article/download/342/293