Callous-unemotional (CU) traits designate an important subgroup of antisocial individuals at risk for early-starting, severe, and persistent conduct problems, but this construct has received limited attention among young children. The current study evaluated the factor structure, psychometric properties, and validity of scores on a comprehensive measure of CU traits, the Inventory of Callous-Unemotional Traits (ICU), in relation to measures of antisocial/prosocial behavior and emotional processing, administered to preschool children. The sample included 214 boys (52 %) and girls (48 %, M age = 4.7, SD = 0.69) recruited from mainstream and high-risk preschools. Confirmatory factor analyses supported a two-factor structure including callous and uncaring dimensions from 12 of the 24 original ICU items. Scores on the parent- and teacher-reported ICU were internally consistent and combined CU scores showed expected associations with an alternate measure of CU traits and measures of empathy, prosocial behavior, conduct problems, and aggression. Preschool children high on CU traits were less accurate, relative to children scoring low, in recognizing facial expressions. They were also less attentionally engaged by images of others in distress when co-occurring conduct problems presented. Findings extend the literature by supporting the psychometric properties of the ICU among young children, and open several avenues for studying early precursors to this severe personality disturbance.