•Original research article• Background: Up to 8% of women in their reproductive years are affected by Premenstral Dysphoric Disorder (PMDD). Sleep disturbances such as insomnia or hypersomnia are one of the DSM-IV-TR's defining criteria for the diagnosis of PMDD and are found in about 70% of women with the disorder. However, studies are lacking that specifically address the effects of PMDD on quality of sleep. Aim: This study was designed to evaluate the prevalence of Premenstrual DysphoricDisorder (PMDD) and its impact on sleep quality in female university students. Methods: We developed an 18-item PMDD scale based on The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) to diagnose PMDD in female university studentswho ranged in age from 18 to 30 years and had regular menstrual cycles.Participants were categorized into a PMDD group or a No/PMDD group and sleep quality was compared between the two groups. The evaluation tool used to measure sleep quality was the Pittsburgh Sleep Quality Index (PSQI). Results: The prevalence of PMDD in female universitystudents was 25.5%. Analysis of the PSQI demonstrated that 80.5% of those in PMDD group had a PSQI that scored >5; however, only 56.4% in the No/ PMDD grouphad a PSQI that scored >5 (χ 2 =12.459, p<0.001). The mean PSQI score was 8.2(3.4) in the PMDD group and was 6.5(3.1) in the No/PMDD group (t=3.648, p<0.001). Conclusions: Female university students who experience PMDD are deeply affected by sleep problems. Lower sleep quality, daytime dysfunction, and sleep disturbance are common sleep problems among female university students with PMDD.