Biological risk factors, such as prematurity, low birth weight and environmental factors, such as social class, can influence children development. The aim of this study was to compare the psychomotor development in three groups of school-age children - (1) preterm from low income families, (2) full term from low income families and (3) full term from middle class. The participants were 120 children, aged 5 to 7 years old, 40 in each group. Children were tested on static balance, postural, perceptual and visual motor skills measures. There was significant difference between groups in the majority of the tests. When analyzing the isolated effect of social class, a favorable effect for middle class in the postural and balance measurements was observed. The results suggest that the development of preterm children, especially in those from socially disadvantaged backgrounds, should be followed up to at least school age. Therefore, it is important to incentive the implementation of developmental follow-up programs in the public health system.