An extensive study of the organic components of the leachate from the University of Connecticut landfill has been carried out. A modification of EPA Method 625 for base/neutral extractable organics was used to obtain both the gas chromatographic profiles and the mass spectrometric identification of the organics in groundwater samples from six test wells and several private wells in the vicinity of the landfill. A characteristic fingerprint representing a number of components was consistently found in the analysis of the landfill leachate but not in the drinking water of the private residences located on an adjoining road. Gas chromatographic parameters for optimum qualitative and quantitative analysis of field samples were determined using an acetone solution of the model leachate sample. It was confirmed that the on-column injection mode resulted in greater flame ionization detector (FID) response and more reproducible peak areas than the splitless mode. The major variable in obtaining reproducible data was the field sampling at the landfill, not the solvent reduction step or the injection mode used to introduce the sample into the gas chromatograph.