Reports about the prevalence of premenstrual symptoms state that occurs in 20 to 100% of most reproductive-age women. There is a close association between premenstrual syndrome and affective disorders as well as same some other psychiatric disorders. Late luteal phase dysphoric disorder (LLPDD) is a premenstrual condition defined in DSM-III-R by severe mood changes and other symptoms that repeatedly occur only in the luteal phase of the menstrual cycle. However, DSM-III-R does not specify how to compute the change from the follicular to the luteal phase or how to determine when the amount of change is great enough to warrant the diagnosis nor how to determine occupational or social functional impairment. This study was conducted to evaluate the nature, severity and magnitude of premenstrual syndrome in women with current psychiatric disorders by using prospective Daily Rating Form(DRF), and to measure symptom changes according to three scoring methods for diagnosing LLPDD. Our study obtains the data about premenstrual changes estimated by DRF from 22 women with psychiatric disorders who had met criteria for major depressive syndrome on the Premenstrual Assessment Form (PAF). The data was scored by each three methods and was determined to meet criteria A for LLPDD. The results are as follows: 1) the subjects, when scored according to the percent change method, effect size method and absolute severity method, met the DSM-III-R criteria A for LLPDD in 36.4% (8 subjects), 14% (3 subjects) and 4.5% (1 subject) of the cases respectively. 2) The items of irritability, anger and impatience were occurred most frequently on the DRF, when it was scored according to the three scoring methods. And the item of breast pain was next frequent according to the effect size method and the percent change method but according to the absolute severity method. 3) The PAF item of impaired social functioning was reported by 16 (73%) of the subjects. 4) 4 (18%) of the subjects met criteria A for LLPDD and reported impaired social functioning. The prevalency of LLPDD according to each method varied. The percent change method yielded the greatest (36.4%), and the absolute seventy method yielded the laest (4.5%), The effect size method yielded an intermediate frequency (14%). Therefore, for maximizing the diagnostic accuracy of LLPDD, a diagnostic procedure including a measure of change (e.q., effect size method, percent change method) as well as confirmed diagnosis by DRF, will be needed. Also, an accurate tool to evaluate impaired social functioning will be required.