This study aims to explore the healthcare utilization (HCU) and expenditures from complementary health insurance among Iranian people who survived sulfur mustard (SM) exposure during the Iran-Iraq war. This study was conducted between March 21, 2018 and March 21, 2019 using secondary data. Data on the HCU and expenditure of war survivors after their exposure to SM were obtained from the Iran Veterans and Martyr Affair Foundation (VMAF) database and the national complementary insurance organization that covers their medical expenses. Multiple linear and zero-inflated poison regression (ZIP) models were used to estimate the costs and HCU. Analyses were performed in R software version 3.6.3. Among 58880 survivors who were included in study, 36383 (61.7%) used at least one service during a year. The total frequency of HCU was 15.6 services per person per year. The annual mean medical cost of each survivor was US$807.6 (±2901.2). The highest number of utilizations was related to medicine and physician visits. The highest median cost was related to rehabilitation (US$151.7), medical equipment (US$84.5), medicine (US$83.3) and inpatient services (US$ 48.8). With increasing age, disability, weight, severity of injury in lung or eye injuries, the rate of health service utilization rose significantly. Over 30 years after the Iran-Iraq war, Iranian people who were exposed to SM and survived still suffer from injuries and pose a significant drain on healthcare resources.