Aims: This study assessed factors contributing to glycemic control among diabetes mellitus patients complying with home quarantine during the epidemic of coronavirus disease 2019 (COVID-19). Methods: We conducted an analytical cross-sectional study by telephone with 1159 patients with type 2 diabetes mellitus (T2DM) and 96 patients with type 1 diabetes mellitus (T1DM) who were discharged from the endocrinology department of a hospital from January 1, 2019, to January 24, 2020. According to their fasting blood glucose (FBG) and 2-h postprandial BG (2hPBG) values, the patients were divided into the well-controlled BG group and the poorly controlled BG group. The main evaluation indicators included sociodemographic variables, health risk variables and adherence to self-management behaviors. Results: In total, 74.46% of the T2DM patients and 64.89% of the T1DM patients had poor glycemic control. T2DM patients with poor glycemic control were more likely to be older (odds ratio (OR): 1.017 [95% confidence interval (CI) 1.003-1.030]; P = 0.013), have fewer than 12 years of education (OR: 1.646 [95% CI 1.202-2.255]; P = 0.002), lack a BG meter at home (OR: 2.728 [95% CI 1.205-6.179]; P = 0.016), have a lower degree of medication compliance (OR: 1.627 [95% CI 1.076-2.460]; P = 0.021), and engage in less self-monitoring of BG (SMBG) per week (OR: 10.884 [95% CI 5.883-20.139]; P < 0.001). Fewer than 12 years of education (OR: 3.031 [95% CI 1.112-8.263]; P = 0.030) was a risk factor for glycemic control in T1DM. Conclusions: Glycemic control among patients with T1DM and T2DM during home quarantine amid the COVID-19 pandemic is poor. Our results showed that more eduction, a higher frequency of SMBG, and improved medication compliance may contribute to glycemic control. Therefore, diabetic patients should be advised to increase the frequency of blood glucose measurements during home quarantine and be re-educated regarding the importance of medication compliance. (c) 2020 The Authors. Published by Elsevier B.V.