Dengue hemorrhagic fever (DHF) disease is one of the problems in healthcare facility. According to WHO criteria, thrombocyte and hematocrit are used as an indicator for the diagnosis of DHF. Hematocrit and thrombocyte examination will help and simplify therapy and diagnosis. The previous studies also stated that body mass index (BMI) has proven to influence the severity of DHF. The aimed is to determine the association between hematocrit, thrombocyte, body mass index and the severity of DHF among adult patients at Esnawan Antariksa Air Force Hospital from January to December 2018.. Subjects and Method: A cross sectional study conducted at Esnawan Antariksa Air Force Hospital East Jakarta, with 68 samples of medical records which were selected for this study. The dependent variable was the severity of dengue hemorrhagic fever, while the independent variables were hematocrit, thrombocyte and body mass index. Result showed a significant level of hematocrit (p=0.000), thrombocyte (p=0.000) and BMI (p=0.245). Conclusion: There were associations between hematocrit, thrombocyte and the severity of DHF among adult patients but none between BMI and severity of DHF patients at Esnawan Antariksa Air Force Hospital. Majority of patients at Air Force Hospital had a normal BMI, which is with normal BMI people had a better immunity than those without.