Many women experience symptoms of premenstrual irritability, reactivity of mood, anxiety, and change in appetite and sleep. Whereas some women experience these symptoms exclusively during the premenstrual phase of the menstrual cycle, others may have premenstrual complaints but actually suffer from mood and anxiety symptoms across the entire menstrual cycle. We sought to determine the extent to which women who seek treatment for premenstrual syndrome (PMS) actually suffer from symptoms of sufficient severity and duration to meet formal criteria for mood or anxiety disorders. Two hundred six women who responded to advertisements for a treatment study of premenstrual dysphoric disorder (PMDD) and who were screened by telephone for study eligibility were included in the current investigation. A telephone questionnaire keyed to the Structured Clinical Interview for Diagnosis (SCID-I/P) was used to screen for the presence of current mood and anxiety disorders. Approximately 39% (n = 80) of respondents met criteria for mood or anxiety disorders or both. Mood disorders were noted almost twice as commonly as anxiety disorders. The high prevalence of mood disorders in the sample underscores the need for clinicians to be aware of the overlap between reported PMS symptoms and underlying depressive disorder. Given that early identification and treatment of mood disorder can increase the likelihood of recovery and lower risk for recurrent illness, clinicians should have a low threshold for ruling out mood and anxiety disorders in women with complaints of premenstrual symptoms.