High-resolution mass spectrometry and potentiometric titration have been applied to the analysis of nitrogen-containing fractions from fuel products derived from hydroprocessed shale oil. Both low and high ionizing voltages were used to obtain the mass spectrometric data. Data obtained with high ionizing voltage was analyzed using the Peters and Bendoraitis method. For chemically stable fractions, this method yielded good agreement with results from potentiometric titration. Agreement was worse for fractions containing reactive pyrrole and arylamine species. Low ionizing voltage data indicated that dimerized species had been produced in these reactive fractions after their isolation. Semiquantitative determination of nitrogen compound types in fuel products from hydroprocessed shale oil is possible using high-resolution mass spectrometry, potentiometric titration, and absorption chromatography.