We examined the sleep electroencephalogram (EEG) in 9- and 10-year-old children with (PH+) and without (PH-) a parental history of alcohol abuse/dependence to determine whether sleep disturbances associated with alcohol precede the onset of alcohol use. Participants slept on a fixed sleep schedule that ensured at least a 10-h time in bed for 1 week before an adaptation and baseline night. Data were collected in a four-bed sleep research laboratory. Thirty healthy boys and girls aged 9 or 10 years were classified as either PH+ or PH- based on DSM-IV criteria applied to structured parental interviews. All-night polysomnography was performed, sleep data were scored visually in 30-s epochs, and EEG power spectra were calculated for each epoch. All-night EEG spectra were calculated for rapid eye movement (REM) and non-REM (NREM) sleep, and cycle-by-cycle spectra were calculated for NREM sleep. The two groups did not differ on any sleep stage variable. All-night analyses revealed normalized power in the delta band and spindle range were lower in PH+ children. Within NREM sleep cycles PH+ children exhibited less normalized power in the delta band and spindle range compared with PH- children. This effect occurred in the first four cycles and was most pronounced in the first sleep cycle of the night. We found no signs of sleep disruption in sleep stages for PH+ children. Sleep EEG spectral differences, however, suggest that certain circuits responsible for 'protecting' sleep may be impaired in PH+ children, which may lead to disrupted sleep later in life.