Object: Interest in the association between female sex hormones and mental diseases is not new. A possible association betweeen schizophrenia and estrogens is remarkable. Research on the subject suggested that, women with schizophrenia have chronic gonadal hypofunction and hypoestrogenism. With regard to the hypotesis claiming; insufficient functioning of the sexual glands and estrogen defficiency in women with schizophrenia, the onset of the puberty may be later. In this study,our aim is to examine whether there is difference between women with schizophrenia and mentally healty women considering the age at menarche. Methods: In this study, we included 289 patients who were diagnosed with schizophrenia and 339 mentally healty individuals from the internal medicine outpatient clinic as control group. SCID-I is used to confirm the disorder in schizophrenia group, and to exclude any mental ilness in the control group. Those with mental retardation or organic brain disorders were excluded from the study. Individuals personal information and age at menarche is determined with a sociodemografic form in consultation with the patient and a relative. Results: Compared to controls, the mean age at menarche was higher in women with schizophrenia, but this difference is not statistically significant. Discussion: This supports hypothesis that hypoestrogenism in women with schizophrenia may be caused by neuroleptic treatment. However the participation of the internal medicine patients instead of the healty controls is the limitation of our study. Internal diseases may have influence on the onset of puberty. [Anadolu Psikiyatri Derg 2014; 15(4.000): 344-349]