Background. Close links between children's capacities to store and manipulate information over brief periods have been found with achievements on standardised measures of vocabulary, language comprehension, reading, and mathematics. Aim. The study aimed to investigate whether working memory abilities are also associated with attainment levels in the national curriculum assessments at 7 years of age. Sample. Eighty-three children aged 6 and 7 years attending local education authority schools participated in the study. Methods. Working memory skills were assessed by a test battery designed to tap individual components of Baddeley and Hitch's (1974) working memory model. Children were assigned to normal and low achievement groups on the basis of their performance on national curriculum tasks and tests in the areas of English and mathematics. Results. Children with low levels of curriculum attainment showed marked impairments on measures of central executive function and of visuo-spatial memory in particular. A single cut-off score derived from the test battery successfully identified the majority of the children failing to reach nationally expected levels of attainment. Conclusions. Complex working memory skills are closely linked with children's academic progress within the early years of school. The assessment of working memory skills may offer a valuable method for screening children likely to be at risk of poor scholastic progress.