This study was conducted to evaluate the neuroprotective effects of Cheonggukjang extract in in-vitro and in-vivo models. T98G-human glioblastoma cells were pretreated with various concentrations (1~10 mg/mL) of Cheonggukjang extract for 24 h and then exposed to H2O2 (1 mM) for 3 h. The neuroprotective effects of Cheonggukjang extract were measured using a CCK-8 kit assay, total antioxidant capacity (TAC) assay, reactive oxygen species (ROS) assay, and lactate dehydrogenase (LDH) release assay. The early stage focal ischemia rodent model was used as the in-vivo neurotoxicity model. Various concentrations (10~200 mg) of Cheonggukjang extract were administered to the animal models for 1 week. Peripheral blood was analyzed for glutathione peroxidase (GPx) expression by ELISA, and infarct volume reduction was analyzed by TTC staining. Cheonggukjang extract significantly (p<0.05) increased cell viability in T98G cells against H2O2 as well as against the induced neurotoxicity. Indeed, treatment with the Cheonggukjang extract induced a decrease in ROS and LDH expression and increased TAC significantly (p<0.05). However, Cheonggukjang extract did not induce a decrease in infarct volume or an increase in GPx expression in the in-vivo model. Despite the limitation in neuroprotection, Cheonggukjang extract may be useful for treating ROS injury.