The purpose of this research was validation, rehabilitation and normalization of Social Skills Rating System (SSRS) (Gresham & Elliot, 1990) for 1001 preschool and 610 kindergarten children (ages 3-6) who were selected using Stratified Cluster Sampling in Tehran. The instruments were preschool level of SSRS-parent form (Gresham & Elliot, 1990) and SSRS-teacher form (Gresham & Elliot, 1990) and also background information on children. A pilot study administered on 100 parents and teachers of preschool and kindergarten children showed adequate psychometric characteristics for measures. Parents and teachers of children in final test answered the Social Skills Rating System- Parent and Teacher forms. LISREL and SPSS softwares were applied for statistically analyzing data. The findings of confirmatory factor analysis provided support for the factor structure of social skills and also problem behaviors in SSRS- parent and SSRS- teacher forms in Preschool and kindergarten levels. Internal consistency of the social skills and problem behaviors’ totals and their subscales in all forms were found to be very satisfactory. Convergent and discriminate validity of the scales were investigated. Significant positive correlations between the scores of cooperation, assertion, responsibility, self-control and social skills’ total and also internalizing, externalizing problems and problem behavior’s total provided empirical support for the convergent validity of SSRS in all of forms. Low negative correlations between social skills and problem behavior scales of SSRS demonstrated the discriminant validity of SSRS- parent and SSRS- teacher forms in preschool and kindergarten levels. The results of a T-test showed that, according to parents and teachers, girls scored higher than boys on social skills subscales (except assertion with no difference between two sexes based on parents’ ratings) and also internalizing behaviors. Boys scored higher than girls on the externalizing problem subscale. The findings support the consistency of SSRS- parent and SSRS- teacher forms in preschool and kindergarten levels factor structures and their validity in measuring social skills, problem behaviors and academic competency (teacher form k-6 level) in Tehran's 3-6 years old children. The norm tables were designed for preschool and kindergarten girls and boys distinctly.