Tau protein is located in the axons of neurons and in Alzheimer Disease, is abnormally phosphorylated and aggregates into paired helical filaments (neurofibrillary tangles) reflecting the degree of neurofibrillary pathology and neurodegeneration. Although tau and phosphorylated tau (p-Tau) pathology is a hallmark for dementia, few studies were performed in patients of schizophrenia. This preliminary serum study was designed to compare serum total tau and p-Tau levels of schizophrenia patients with healthy controls. The study was included 42 patients diagnosed with schizophrenia and 42 healthy control subjects. Sociodemographic form was applied to both groups and PANSS was applied to patient group. Serum total tau and p-Tau levels were measured by ELISA method. Total tau and p-Tau levels of patients were significantly lower than healthy controls. There was a positive correlation between amount of past electroconvulsive therapies and total tau level. However total tau and p-Tau levels were positively correlated. Our study results showed that serum total tau and p-Tau levels of patients with schizophrenia were significantly lower than healthy controls.