A longitudinal comparative study was made of the physical growth and development of Australian fourth-grade students from low, medium, and high socioeconomic groups. Specific questions addressed were (1) Do children differing in socioeconomic status differ in anthropometric characteristics and incidence of physical defects? (2) What is the incidence of physical defects among 9-year-olds, and is the incidence of physical defects associated with lower school achievement? (3) Are differences in school achievement levels and IQ related to anthropometric differences? and, (4) Have the stature and weight of 9- and 10-year-olds increased since 1970? Findings indicated that physical defects were no greater within an economically disadvantaged group than in a more advantaged group. Defects were not found to be associated with lower levels of school achievement. However, significant differences were found in the mean height, weight, and head circumference of disadvantaged and advantaged children. Mean height for both males and females increased over the period between 1970 and 1982-83. Findings supported the claim that height and educational achievement are positively related within each socioeconomic group. (Appended are the medical record form used and other related materials, including a screening test for speech and language, speech therapy data, and a staff conference paper describing the Mt. Druitt longitudinal study and reporting results of the 1982 survey of fourth-graders' physical development and health.) (RH)