BACKGROUND Alcoholic patients show prominent disturbances of sleep electroencephalograms (EEGs) with a marked loss of slow wave sleep that is even more profound in African American alcoholics as compared to European Americans. Using partial sleep deprivation, this study examined the extent to which abnormal sleep is reversible in alcoholic subjects. METHODS In a sample stratified on ethnicity, polysomnographic and spectral sleep EEG measures were compared in male primary alcoholic in patients (n=46) and age-matched comparison controls (n=32) at baseline-and recovery sleep following a night of partial sleep deprivation. RESULTS As compared to controls, alcoholic patients showed a loss of slow wave sleep and more spectral power in beta frequencies. Following sleep deprivation, slow wave sleep and delta power differentially changed between the groups. European American controls showed increases of slow wave sleep that were more robust than responses found in African American controls, whereas both alcoholic groups failed to show increases of slow wave sleep from baseline to recovery. Spectral EEG analyses revealed similar results; sleep deprivation induced significant increases of delta power during NREM-1 in the controls, but not in the alcoholics. CONCLUSIONS Alcohol dependence compromises the augmentation of slow wave sleep and delta power seen in healthy adults following sleep deprivation. The differential effect of alcoholism on sleep stage physiology suggests a defect in the regulation or plasticity of slow wave sleep with implications for theories linking sleep depth to morbidity and outcome in alcoholics.