BACKGROUND: Depression is a common mental disorder in people with type 2 diabetes mellitus (T2DM). Depression and T2DM have a reciprocal interaction through many factors, of which the most important is the multifactorial control and microvascular complications of T2DM. AIM: This research aims to determine the rate of depression and the association between depression and multifactorial control and microvascular complications in patients with T2DM aged 30-60 years in Vietnam. METHODS: A cross-sectional and descriptive study was conducted on 231 outpatients with T2DM at Bach Mai hospital, Hanoi, Vietnam. Depression severity was measured with the Patient Health Questionnaire-9 (PHQ-9). RESULTS: The rate of depression in patients with T2DM aged 30-60 years was 16.9% (in which, the rate of mild depression was 15.2% and moderate depression was 1.7%; no serious depression). The prevalence of depression was higher in female patients than in male patients (p = 0.049). There is a statistically significant difference in the rate of depression by age, duration of diabetes, and treatment method for type 2 diabetes. Poor HbA1c control and microvascular complications increase the risk of depression (OR = 2.37; 95% CI 1.11-5.02, p = 0.033 and OR = 2.62; 95% CI 1.15-5.93, p = 0.027, respectively). When the multivariate analysis was performed, it was shown that sex, treatment for glycemic control, and microvascular complications had a statistically significant influence on PHQ-9 score. CONCLUSION: In Vietnam, there are 16.9% of patients with T2DM aged 30-60 years suffer from depression. Poor HbA1c control, the presence of microvascular complications, and without antihyperglycemic treatment increase the risk of developing depression.