Traditional measures of intelligence frequently yield low scores when applied to disadvantaged subjects. This study tests whether similar findings would result from measures of developmental behavior. Accordingly, the developmental behavior of 159 culturally disadvantaged children (85 boys, 74 girls) was assessed by systematic interviewing of preschool and elementary school teachers using the Preschool Attainment Record (PAR). The children, enrolled in the Education Improvement Program (EIP) in Durham, North Carolina, were members of nine groups attending nursery, preschool, or ungraded primary school. Mean group ages ranged from 24.7 to 93.5 months. The results, by groups, are graphed and analyzed with respect to attainment age, attainment quotient, and the ambulation, manipulation, rapport, communication, responsibility, information, ideation, and creativity subscales of the PAR. Scores on the PAR are also compared with group mean scores on age-appropriate IQ measures. A steady decline in the rate of achievement and noticeable sex differences in performance appear as age increases. The measure proved useful and informative for evaluation purposes in this education improvement program for the culturally disadvantaged. Replication of the study with the same group and comparison with control groups are recommended to check the reliability of the findings. (LR)