A relationship between motor ability and cognitive performance has been previously reported. This study aimed to investigate the association between movement and cognitive performance at 1 and 4 years corrected age of children born less than 1000 g, and whether developmental testing of movement at 1 year is predictive of cognitive performance at 4 years. Motor development was assessed at both ages using the neurosensory motor developmental assessment (NSMDA) and motor development was classified as normal, or minimal, mild, moderate-severe dysfunction. Cognitive performance was assessed on the Griffith Mental Developmental Scale at 1 year and McCarthy Scales of Children's Abilities at 4 years. Subjects included 198 children of birthweight less than 1000 g. Of these 132 children returned for follow-up at the corrected ages of both 1 and 4 years. The 66 children not included had a slight increase in gestational age, while the mothers were younger and had a lower level of education. A significant association was found between NSMDA group classification at 1 year and cognitive performance at both 1 and 4 years (p<0.001; p<0.0001) and between the subscales of each test (1 year, p<0.0001; 4 years, p<0.001). Group classification of motor development at 1 year was predictive of cognitive performance at 4 years (p<0.0001) and this was independent of biological and social factors and presence of cerebral palsy (CP). The findings support a close link between motor and cognitive development in children born <1000 g and emphasise the advantage of detailed assessment of movement at 1 year.