The mismatch negativity (MMN) event-related potential (ERP) component is an automatic, attention-independent brain response to auditory stimulus change, which has been reported to be smaller in alcoholics relative to nonalcoholic controls. To determine whether MMN decrements might be a trait marker of alcoholism that is also present in nonalcoholic individuals at high risk for developing alcoholism, we investigated MMN in 9- to 18-year-old children of alcoholics (n = 20) and control children (n = 20) in three different stimulus conditions using a passive auditory oddball paradigm. There were no statistically significant between-group differences observed in amplitude, scalp topography, and peak latency of MMN. These findings, if replicated, suggest that reported MMN decrements in alcoholics most likely represent a state marker, and not a trait marker, of alcoholism. Also, inasmuch as another ERP component, the P300, is attention-dependent and reported to be smaller in children of alcoholics, the present results implicate that deviations in attentive, but not in automatic, information processing are associated with alcoholism vulnerability.