Aim: schizophrenia and the psychopathology, risk of relapse, symptom severity, the side effects after antipsychotics and schizophrenia subtypes are known. The aim of this study is to examine the serum PRL level difference between drug naive schizophrenia patients and healthy control group and between schizophrenia subtypes. Material and Method: 45 untreated volunteer participant between the ages of 18-55 who applied to Ankara Numune Training and Research Hospital, in patient and outpatient departments of Psychiatry, diagnosed with schizophrenia with the DSM IV-TR classification were included to study before getting treated. Participants were given sociodemographic information form; Axis-II for definitions Semi-Structured Clinical Interview, the Positive and Negative Syndrome Scale (PANSS) and Global Assessment of Functioning Scale (GAF) and biochemical measurements were made. Results: The mean serum PRL levels in drug naive patients with schizophrenia were higher compared to the control group (p = 0.004). When patients with schizophrenia divided in to two groups as "paranoid" and "non-paranoid", the mean serum prolactin levels among these groups were significantly different (p = 0.000). There was no significant relationship between serum PRL levels and GAF scores (P = 0.116) or PANSS total scores (P = 0.676) in patients with drug naive schizophrenia. Discussion: The difference between mean serum PRL levels in drug naive schizophrenia patients and schizophrenia subtypes are consistent with studies in the literature. As to use PRL levels as a marker in the clinic, further studies are needed.