Abstract Background & Objectives: Premenstrual syndrome is a common disorder and is assessed by various diagnostic tools. However, there is no world or national agreement on a single diagnostic criteria for this syndrome. This study was designed to develop and validate an scale for assessment of premenstrual syndrome in Sabzevarian adolescents in the year 2011. Material & Methods: In this methodological study, some focus group and individual interviews were conducted with high school female students to determine the elements of the scale through purposive sampling. Based on the results of the qualitative interviews and the symptoms reported in some diagnostic criteria, the new scale was developed and its face, content and construct validities were assessed. Furthermore, its reliability was estimated using internal consistency. SPSS software version 16 were used for data analysis. Results: Thematic analysis of the data concerning the symptoms obtained from interviews resulted in two major dimensions of somatic and emotional-behavioral symptoms. Content validity ratio and index were 0.78 and 0.9 respectively. Explanatory factor analysis could also extract two correlated factors that jointly accounted for 37% of the variance. The resultant scale demonstrated the Cronbach's alpha coefficient with values of 0.915 and 0.791 for the first and second factor. Conclusion: The new developed scale is a reliable and valid criteria for premenstrual syndrome in Iranian female adolescents.