We aimed to evaluate the validity of the Ages and Stages Questionnaires Edition 3 (ASQ-3) and the MacArthur communicative development inventory (CDI) as a screening measure for children at risk of language development delay in western rural China, by comparing them to the Bayley Scales of Infant and Toddler Development (BSID-III). We administered the BSID-III on 1,079 children (aged 8-24 months) and administered the ASQ-3 and the CDI to their caregivers. We found a significant, low-to-moderate correlation between the three scales. Further, correlation strength increased with age of the child and was stronger when the mother was the primary caregiver. We also found that the sensitivity and specificity of the ASQ-3 ranged widely. The overall findings suggest that the ASQ-3 and the CDI may not be very accurate screening tools for identifying language development delays in children, especially those under 17 months or whose primary caregiver is not their mother.