Background: The late positive potential (LPP) is an event-related potential component that indexes selective attention toward motivationally salient information and is sensitive to emotional stimuli. Few studies have examined the LPP in children. Depression has been associated with reduced reactivity to negative and positive emotional stimuli, including reduced LPPs in response to emotional faces. The current study sought to identify the time course and scalp distribution of the LPP in response to emotional faces in young children and to determine whether reduced reactivity is observed among children at risk for depression. Methods: Electrocortical reactivity to emotional faces was examined in a large sample of young children and as a function of maternal and paternal depression. Results: In the overall sample, emotional faces were associated with increased positivities compared to neutral faces at occipital sites 200-600 ms after stimulus onset and at parietal sites 600-1,000 ms after stimulus onset. Children of mothers with a history of depressive disorders exhibited reduced differentiation in the early occipital LPP for emotional compared to neutral faces. Conclusions: Results suggest that children as young as 6 years exhibit LPPs to emotional faces, and patterns of electrocortical reactivity to emotional stimuli may be associated with vulnerability to depressive disorders.