Type 2 diabetes mellitus (T2DM) is a global health issue that affect around 643 million people in 2030. Estimated prevalence of T2DM in adults aged 20–79 years has more than tripled, from an estimated 151 million (4.6% of the global population at the time) to 537 million (10.5%) today. This study analyze direct medical costs of insulin treatment with in T2DM outpatients. This retrospective descriptive economic evaluation was conducted in April 2023 on the basis of payer (called as Badan Penyelenggara Jaminan Sosial abbreviated as BPJS) perspective, then only direct costs were included in this study. Component of direct medical cost of this research include drug acquisition costs, physician service, laboratory examination, medical execution and administration. 58 T2DM outpatients met inclusion criteria in Universitas Sumatera Utara was recruited by simple random sampling. Result of this study show that most of respondent were aged 56-65 years (58.89%). Cost/year/patient of drug acquisition costs was Rp.4,7228,970.14; physician service was Rp.1,865,172.41; laboratory examination was Rp.443,379.31; and medical execution was Rp.31,030.48 and administration was Rp.300,000.00, respectively. Drug acquisition costs was the largest cost in treating T2DM patients with insulin treatment.