Background. The anaesthetic dose causing neurotoxicity in animals has been evaluated, but the relationship between duration of volatile anaesthetic (VA) exposure and neurodevelopment in children remains unclear.Methods. Data were obtained from the Western Australian Pregnancy Cohort (Raine) Study, with language (Clinical Evaluation of Language Fundamentals: Receptive [CELF-R] and Expressive [CELF-E] and Total [CELF-T]) and cognition (Coloured Progressive Matrices [CPM]) assessed at age 10 yr. Medical records were reviewed, and children divided into quartiles based on total VA exposure duration before age three yr. The association between test score and exposure duration quartile was evaluated using linear regression, adjusting for patient characteristics and comorbidity.Results. Of 1622 children with available test scores, 148 had documented VA exposure and were split into the following quartiles: ≤25, >25 to ≤35, >35 to ≤60 and >60 min. Compared with unexposed children, CELF-T scores for children in the first and second quartiles did not differ, but those in the third and fourth quartiles had significantly lower scores ([3rd quartile – Unexposed] -5.3; 95% confidence interval [CI], (-10.2 – -0.4), [4th quartile – Unexposed] -6.2; 95% CI, (-11.6 – -0.9). CELF-E showed similar findings, but significant differences were not found in CELF-R or CPM for any quartile.Conclusions. Children with VA exposures ≤35 min did not differ from unexposed children, but those with exposures >35 min had lower total and expressive language scores. It remains unclear if this is a dose-response relationship, or if children requiring longer exposures for longer surgeries have other clinical reasons for lower scores.