Six cases of neonatal infection with Listeria monocytogenes occurring in Seattle, Washington, a previously unreported and apparently unsuspected endemic area are reported. A review of the case reports in the United States and Canada are discussed and the manifestations of the disease in the pregnant mother and infant are characterized. An effort has been made to analyze mortality and its relation to specific antibiotic therapy and individual antibiotic disc sensitivities, as well as to the possible predisposing factors involved in the infection. The findings would suggest that the high mortality and morbidity in this disease might be lowered if a high index of suspicion is combined with adequate and prompt culturing techniques. Specific antibiotic therapy should be selected by sensitivity testing since it appears that standard therapy for unknown sepsis is not always adequate to significantly lower the mortality. Consideration should especially be given to the use of a tetracycline if Listeria is suspected in the very early neonatal period.