The aim of the study was to assess the clinical similarities and common features of fibromyalgia syndrome (FM) and premenstrual dysphoric syndrome (PMDD). Thirty young patients who met the diagnostic criteria for PMDD were included in the study and compared to 26 women belonging to the medical staff of a general psychiatry department. All enrollees were interviewed and examined by a skilled physician. They completed the following nine survey items: demographic information, clinical health assessment questionnaire, fibromyalgia impact questionnaire, sleep and fatigue questionnaires, Sheehan disability scales, SF-36 assessment for quality of life, visual analog scale for pain, Mini International Neuropsychiatric Interview (MINI) questionnaire (assessment of coexistent psychiatric conditions), and the premenstrual severity scale. Additionally, each individual underwent a physical examination measuring the classical tender points and was asked to describe the distribution and continuum of her pain or tenderness. The PMDD group scored significantly higher in the measures pain and tenderness as well as in severity of premenstrual symptoms compared to the control group. Five patients in the PMDD group and none in the control group had FM. Quality of life measured by the SF-36 was higher in the control group than in the PMDD group and correlated with the degree of tenderness reported. Psychiatric comorbidity was significantly more common in the PMDD group, affecting 16 of the 30 PMDD patients compared to only three of the 26 control patients. In this study, patients with PMDD were found to have higher levels of tenderness, higher psychiatric comorbidity, greater level of physical disabilities, and a lower quality of life. These parameters were highly correlated with a lower pain threshold.