A major goal of pharmacogenetic research on alcoholism remains the identification of some "marker" that could predict the liability of a particular individual for a genetic susceptibility to develop alcoholism. The present paper presents evidence that the severity of withdrawal from physical dependence on ethanol varies widely among inbred strains of mice, and that withdrawal severity is negatively genetically correlated with initial sensitivity and magnitude of tolerance to ethanol hypothermia. These correlations are supported by differences in hypothermic response between replicate lines of mice genetically selected for susceptibility and resistance to ethanol withdrawal seizures. The genetic relationships reported suggest that the effects of ethanol on thermoregulation in mice may offer a predictive marker for susceptibility to ethanol physical dependence.