Kieu TTM, et al. - This study was carried out to calculate the direct non-medical costs and indirect costs due to type 2 diabetes mellitus (T2DM) and its associated complications among Vietnam Health Insurance System (VHIS) enrollees in Vietnam. Between 1 June and 30 July 2018, A sum of 315 individuals from a national hospital, a provincial hospital and a district hospital aged 18 or above, diagnosed with T2DM, enrolled in VHIS and having at least one visit to hospitals were included. The initial phase was a cross-sectional survey of individuals with T2DM. In the second phase, data from the previous phase were applied to prognosticate direct non-medical costs and presenteeism costs of VHIS enrollees diagnosed with T2DM based on demographic, and clinical characteristics in 2017. They applied the human-capital approach for the estimation of indirect costs. The effect of T2DM on direct non-medical and indirect costs on diabetes is important. In individuals with complications, direct non-medical and absenteeism costs were higher.