This research has been carried out with the aim of adaptation and study of psychometric properties and practicality of Snijders-Oomen nonverbal intelligence test for 21/2-7 years children (SON-R 21/2-7) for Persian speaking children. In this study, 2852 children (1456 boys and 1396 girls) were selected from nursery schools of the city of Tehran which are under control of Tehran's welfare organization by means of multistage stratified random sampling method. In order to analyze data, classical model and two-parameter logistic model were used. Internal consistency of subtests (Mosaics, Categories, Situations, Puzzles, Analogies and Patterns) were obtained by l2 formula, and reliability of performance and reasoning scales and total scores estimated by stratified alpha. The range of reliability coefficient for subtests were 0.81 to 0.88 and reliability coefficient of performance and reasoning scales and total scores were 0.88 to 0.95. Various analyses were carried out about validity, including exploratory and confirmatory factor analysis, intercorrelation of subtests, item-total correlation, correlation of subtests with scales and total scores, age discrimination and discrimination power. Norms were provided for subtests, scales and total scores for all age groups (2, 3 to 7, 12) in six month intervals. On the whole, the results obtained from this research showed that reliability and validity of the test are high and it can be used to measure total intelligence of children.