Premenstrual syndrome (PMS) is a heterogeneous disorder, which includes physical, cognitive, affective and behavioral symptoms. The aim of this study was to determine the factors affecting PMS and the relationship between PMS and alexithymia. The research was performed with 308 students. Data were collected using a demographic questionnaire, the Toronto alexithymia scale (TAS-20) and a premenstrual assessment form (PAF). The prevalence of PMS in our sample was 66.6%. The contributing factors to PMS were having a history of psychiatric treatment and having a smoking habit (p<0.05). The PMS group showed higher scores than the non-PMS group on all the items of the TAS-20 which includes the three factors: difficulty in identifying feelings, difficulty in describing feelings and externally oriented thinking (p<0.05). The alexithymic students showed higher scores on all PAF subscales (p <= 0.001). Further studies are needed to determine the probable role of alexithymia in the pathogenesis of PMS.