Objectives: Our recent studies have demonstrated that the brain's automatic change-detection response, the mismatch negativity (MMN) of the event-related brain potential (ERP), is significantly attenuated in school-age children with CATCH syndrome and in children of the same age with cleft palate but without the CATCH syndrome. Among other problems, various kinds of learning difficulties are commonly reported in these patient groups. The present study aimed at investigating whether the MMN is attenuated already in newborns with cleft palate compared with healthy controls. Methods: Stimuli of 1000 Hz were presented frequently and 1100 Hz infrequently to 9 neonates with cleft palate and to 8 healthy controls. Infrequent 1100 Hz stimuli elicited a prominent MMN in all of the healthy children, but only in 3 of the 9 infants with cleft palate. Results: A significant difference in the mean amplitudes of responses to deviant tones between the healthy and cleft palate neonates was found. Conclusions: MMN may indicate brain dysfunctions long before they have manifested themselves in cognitive disabilities, which would enable one to identify the infants with an elevated risk and to start their rehabilitation much earlier than before. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.