Objective: Standardizing the Vineland Adaptive Behavior Scale among Iranian population from birth through 18 years and 11 months of age. Method: The Scale is consisted of four domains: Communication, daily life skills, socialization and motor skills. To validate this Scale on Iranian population, 1650 normal subjects composed of 15 age groups in urban and rural areas in Fars, Khorasan, Zanjan, Kohkilouyehboyr'ahmad, and Tehran provinces were selected, Also 130 mental retarded subjects were chosen to be assessed by this Scale. To determine the reliability of the Scale, it was performed on 140 parents of the subjects with retest method. Findings: The findings indicate that the items of this Scale is valid and reliable on Iranian population. Also the table of standardized scores were calculated with 2, 3, and 4 months intervals, adaptive levels in the fields, compound adaptive behavior, the level of maladaptive behavior, percentile ranks, normalized scores, age equivalents in the fields and subfields, and the compound parts of adaptive behavior. Result: This Scale is valid to assess adaptive behavior on Iranian population and has the ability to differentiate between mentally retarded individuals and normal groups. Hence, the differential validity of the Scale may be considered as yet another measure for the structure reliability.