Introduction: Type 2 diabetes mellitus (T2DM), especially those with complications, requires lifelong care and incurs substantial expenses. In order to reduce out-of-pocket costs borne by patients, understanding costs including direct non-medical cost is important. This study aims to examine direct non-medical cost and related factors among T2DM with complications. Methods: A cross-sectional survey of 617 T2DM patients conducted at Thong Nhat and Nguyen Tri Phuong hospitals from May 2023 to July 2023 using convenience sampling method. Generalized linear regression models were used to examine the effect of having complications on direct non-medical cost and other associated factors. Results: The average direct non-medical costs amounted to 1,351,706 VND. For individuals with complications, the average direct non-medical cost was 1,716,756 VND, nearly 1.81 times higher than those without complications. Regarding type of complications, having both complications incurred higher cost than those without complications (245631.8, 95%CI: 29952.3-461311.4, p=0,026), adjusted for other factors. The factors associated with direct non-medical costs included place of residence, educational attainment, having health insurance, traveling with a family member, using personal or public transport, using supplementary foods, and the patient’s income (p <
0.05). Conclusion: This study, among the first to analyze differences in direct non-medical costs among T2DM groups with complications in Vietnam, could contributes to understanding the economic dimensions of T2DM and provide valuable insights for future interventions aimed at alleviating the economic burden of T2DM on patients and society.