The impact on quality of ground water beneath a municipal sanitary landfill in fine-grained, rhythmically-bedded glacial drift in eastern Connecticut was investigated over a sixteen-month period. Chemical analyses of ground water for selected dissolved inorganic constituents indicate significant contamination of shallow ground water only in the immediate vicinity of the landfill. The distribution of these constituents is in general agreement with predictions based on the map of the water table. Concentrations of leachate in shallow ground water beneath the landfill correlate with seasonal fluctuations of the water table, with high concentrations corresponding to periods when the water table is above the base of the landfill.