Retort water samples collected from the Laramie 10-ton simulated in-situ retort were examined by both electron impact (EI) and chemical ionization (CI) mass spectrometry with a Finnigan Model 3300 gas chromatograph--mass spectrometer (GC-MS). These water samples, formed in retorting Green River oil shale of either Utah or Colorado origin, were filtered, lyophilized, extracted with benzene, and esterified. Both the benzene concentrates, as well as the corresponding methylated fraction were studied. Specific compounds were identified by comparison of EI to known spectra and followed by CI with methane as reagent gas. In general, classes of compounds included n-paraffins, fatty acids, phenolics, substituted benzenes, and nitrogen bases. The presence of acids such as stearic, palmitic, myristic, and lauric may be indicative of the algal components in shales which are precursors of kerogen. On the other hand, compounds such as substituted xylenes and phenols may be formed from thermal decomposition in retorting.