We report the first case of an obstructive hydrocephalus after intraventricular hemorrhage in a woman with HELLP syndrome and eclampsia. A 25-year-old primiparaous woman had severe preeclampsia at 36 weeks of gestation. She complained of epigastric pain and nausea. The levels of AST, ALT, and LDH were 539, 560, and 1051 IU/L, respectively; the platelet count was 101 x 109/L. Cesarean section was promptly performed. Intraoperatively, she had a first convulsion. The CT scan revealed only mild brain edema. The platelet count deteriorated to 30 x 109/L at 5 hour after the operation, and she had a second convulsion with an intraventricular hemorrhage. On the 6th post-cesarean day, she complained severe headache followed by coma. The CT scan revealed the enlargement of both lateral ventricles, indicating the occurrence of obstructive hydrocephalus. Drainage into cerebral ventricle was performed, resulting in the recovery of consciousness to a normal level.