The objective of this study was to examine the construct validity and bias of a child health interview (CHI) instrument to assess young children's food and activity preferences. A quantitative study examining the construct validity and bias of a young child health interview instrument using confirmatory factor analysis (CFA) and multi-group CFA examining whether the measurement model of the instrument is equivalent (or invariant) across different child age groups. We collected child interview data from 783 children (3-year-olds = 307; and 4-year-olds = 476) across 20 childcare sites in North Carolina during fall 2017 and spring 2018. To assess the factorial validity of the survey for children of different ages, we conducted group-specific CFAs using the 3- and 4-year-olds' responses and conducted a multi-group CFA. The model fit indices indicate the hypothesized structure of the model fits the data well and subscale factor loadings are significantly related to each of their respective domains. The multi-group analysis demonstrates configural and scalar invariance across the two groups (3- and 4-year-olds), indicating the two groups can be pooled together for further analysis. This study presents some initial evidence of the construct validity of the CHI instrument. The results of the age-group-specific CFAs and multi-group CFA indicate there is no evidence of construct bias for young children of different ages.