Introduction: Preeclampsia becomes the main cause of both maternal and perinatal morbidity and mortality. Growth stimulation gene-2 (ST2) is a protein as sign of vascular inflammation, especially soluble ST2 (sST2). This study aims to determine the sST2 concentration on preeclampsia patients without and with complication. Materials and methods: This analytical observational study using cross-sectional design was conducted at the Polyclinic and Emergency Installation, Department of Obstetrics and Gynecology, Dr. Cipto Mangunkusumo Hospital/Faculty of Medicine, Universitas Indonesia, and Budi Kemuliaan Hospital from August to December 2015. We recruited all pregnant women with normal blood pressure and severe preeclampsia to know the difference between maternal blood sST2 on normal blood pressure, severe preeclampsia without and with complication patients. All statistical analysis was done by Statistical Package for the Social Sciences (SPSS) version 19.0. Results: There were 63 subjects consisting of 23 normal blood pressure pregnant women, 19 preeclampsia without complication, and the other 21 preeclampsia with complication. Kruskal–Wallis test pointed out that there was statistical significance among groups (p < 0.001) and significant result between groups (p < 0.001) in Mann–Whitney test. Post hoc analysis indicated that there were significant differences of sST2 level among three groups. The area under the curve (AUC) of sST2 was 96.1% [p < 0.001; 95% confidence interval (CI) 91.8–100%]. The cut-off of sST2 level in this study was 96 ng/mL with 82% sensitivity and 78% specificity. Conclusion: There is significant difference of blood plasma sST2 level among normal blood pressure and preeclampsia without and with complication group.