Objectives To establish the normative data of the Bayley Scales of Infant DevelopmentSecond Edition (BSID-II) on Taiwanese infants from age 6 to 24 months and to explore the factors that relate to their mental and motor development. MethodsFive hundred and seven Taiwanese full-term infants were prospectively examined with the BSID-II at 6, 12, 18, and 24 months of age.ResultsTaiwanese infants Bayley mental and motor raw scores were lower than the United States norms from age 6 to 24 months, however, the discrepancy gradually declined with increasing age. Gender, intrauterine growth status, birth order, region of residence, maternal education , and paternal occupation were shown to have longitudinal associations with their mental and/or motor scores. ConclusionsDifferences existed in the mental and motor development among Taiwanese and American infants. Our preliminary norms of the BSID-II may be more appropriate than the United States norms for Taiwanese children. ; 醫學系小兒科 ; 醫學系 ; 醫學院 ; 期刊論文