Abstract: Objective To assess the corelation between sleep quality and anxiety in patients with type 2 diabetes mellitus (T2DM). Methods Cluster sampling was used in the study. Each patient completed a version of the Self-designed questionnaire, Pittsburgh sleep quality index and the Self-rating Anxiety Scale questionnaire. Laboratory testing as glycosylated hemoglobin A1c (HbA1c) were measured. The χ² test was used to calculate the difference in categorical data. Anxiety was treated as the dependent variable by adopting multiple logistic regression. Results A total of 578 questionnaires were collected. The rate of poor sleep quality was 31.83% among T2DM patients. The prevalence rate of anxiety was 44.12%. Stratifying according to sleep quality, the prevalence of anxiety was 35.53% in the good sleep quality group, and the prevalence of anxiety was 62.50% in the poor sleep quality group. The difference was significant between the two group (χ²=37.00, P<0.001). Stratifying according to whether the patients achieve successful blood glucose control, the difference was not significant in the group of acceptable blood glucose control (χ²=1.45, P=0.228). The difference was significant in the group of unacceptable blood glucose control (χ²=37.82, P<0.001). After adjustment for confounders (such as gender, ages, the level of education, diabetes complications, depression etc), poor sleep quality was positively associated with anxiety in T2DM patients (OR=2.73, 95% CI:1.87-3.98). Sleep-related factors (perceived poor sleep quality, sleep disturbance and daytime dysfunction) were correlated with the risk of anxiety in T2DM patients (OR=1.84,1.82,2.49). Conclusions Sleep quality is inversely associated with anxiety in T2DM patients.