Despite their importance for developing higher-level reasoning and communication skills, science and engineering represent domains that are often untaught and untested in pre-kindergarten (Evangelou et al., 2010; Greenfield et al., 2009). Science assessment is not common, in part, because measures of young children's scientific knowledge are not currently available for at-scale use. In a sample of 327 children (mean age 4.45 years) from predominately low-income backgrounds, we examined the psychometric properties of a new screening measure of young children's science and engineering knowledge. We present findings regarding test-retest reliability, internal consistency, construct validity, and concurrent validity of the new measure. Results indicate adequate psychometric properties across examined areas for the new measure, including strong concurrent correlation (r=.80) with a standardized diagnostic science measure, the Preschool Science Assessment (Greenfield et al., 2014). However, both science measures were moderately correlated with children's general vocabulary knowledge (r=.65–.70), indicating overlap between these constructs. Discussion focuses on the importance of measuring young children's science and engineering knowledge as a first step toward increasing teachers' awareness of these high-priority instructional domains.