Polycyclic biomarkers such as steranes, diasteranes and tri-, tetra- and pentacyclic terpanes in the hydrocarbon fraction of oils were studied by gas chromatographic/mass spectrometric (GC/MS) analysis in order to correlate six crude oils. Distribution and abundance of these biomarkers were determined for the samples from the Kikinda, Mokrin (Vojvodina) and Požarevac oil fields (two samples for each oil field). The SIM (single-ion monitoring) method was used for the analysis of steranes and terpanes. Individual steranes, terpanes and their stereoisomers were identified by the comparison of obtained retention times with those quoted in the literature. On the basis of the results obtained, it can be concluded that the oils from the Kikinda and Mokrin (Vojvodina) fields belong to the same genetic type, while the oil from the Požarevac field belongs to another type. It was also found that the oils from the Kikinda and Mokrin fields were of a higher degree of maturity than the oils from the Požarevac field.