BACKGROUND: Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and accumulate in humans. PFAS are suspected to affect the neuropsychological function of children, but only few studies have evaluated the association with childhood attention and executive function.OBJECTIVES: To investigate the association between intrauterine exposure to PFAS and offspring attention and executive function.METHODS: A total of 1593 children from the Danish National Birth Cohort, born 1996-2003, were included. The levels of 16 PFAS were measured in maternal plasma during pregnancy. At 5 years of age, the Test of Everyday Attention for Children at Five (TEACh-5) and the Behavior Rating Inventory of Executive Function (BRIEF) were performed. TEACh-5 scores were standardized to a mean of 0 and standard deviation (SD) of 1. BRIEF scores were standardized to a mean of 50 and a SD of 10. The associations between levels of seven PFAS and TEACh-5 and BRIEF were examined by multivariable linear regression adjusted for potential confounders.RESULTS: Perfluorooctane sulfonamide (PFOSA) was associated with poorer selective attention [standardized mean difference (95% confidence interval) -0.5 (-0.7, -0.3), highest versus lowest quartile]. Other PFAS were not clearly associated with selective attention, and we found no clear associations between PFAS exposure and sustained attention. For parent rated executive function, perfluorooctanoate (PFOA) was associated with poorer scores, standardized mean difference 3.8 (95% confidence interval 1.6, 6.0), highest versus lowest quartile. Regarding other PFAS, the associations were less clear. We found no clear associations between any PFAS and executive function rated by preschool teachers.CONCLUSION: Intrauterine exposure to PFOSA was associated with poorer selective attention, while PFOA was associated with poorer executive function. Given the widespread nature of PFAS exposure, these findings may have public health implications, warranting further investigation.