In this study of 167 neonates who demonstrated a total of 1010 transitions between arousal states, we considered whether specific state transitions were associated with umbilical cord blood lead levels. We found that the arousal patterns of neonates with varying levels (<1, 1-10 and >10 microg/dL) of lead exposure could not be distinguished based on the NBAS scoring system alone, but their transition state patterns revealed striking differences. Specifically, the neonates with the highest lead levels were more fidgety, had more state transitions from state 5 or 6, and were least likely to fall from awake states back into lower states. Arousal state transition pattern is thus a novel correlate of umbilical cord blood lead that may be useful for risk stratification of the neonates.