The distribution of low-molecular-mass nitrogen-containing components of oils and dispersed organic matter in the Upper Jurassic play of Western Siberia has been studied. It has been found that their amount in the organic matter of rocks is higher than that of corresponding oils. In all test samples, low-molecular-mass nitrogen compounds are represented by a mixture of strong and weak bases. The qualitative composition of these compounds is the same. The nitrogen bases of the dispersed organic matter differ from petroleum bases by an increased amount of weakly basic components and structures with unhindered nitrogen atoms.