In the current research, three water samples were gathered from Kavala region in Greece: two marine water samples, one from the Central Port of Kavala (PORT) and the other one from the Filippos B Port (BK) at the Eastern Kavala coast, close to the on-shore premises of the local oil-producing company. Moreover, an additional surface water sample (KO) was collected from a reserve pit inside the oil company premises, known to be contaminated by crude oil. It is worthy of remark that Kavala is the only oil-producing region in Greece. The aforementioned samples were compared with an extracted crude oil sample (CROIL) from oil company and two refined petroleum products, one marine diesel (PPR1) and one auto diesel (PPR2), as potential contaminants. The technique used to identify the oil types of the examined samples in the current study was gas chromatography – mass spectrometry (GC-MS). There was a clear differentiation between CROIL and PPR1 and PPR2 peak distribution patterns in all three samples. The comparison between CROIL and KO samples revealed identical GC-MS distribution patterns of biomarkers in m/z 191 (terpanes), m/z 217 (steranes) and m/z 231 (triaromatic steranes). On the other hand, the comparison between CROIL and PORT samples at 57, 191 and 231 m/z showed several important differences. Despite the fact that crude oil is a major suspected pollutant, no correlation can be identified. Nevertheless, small values of Pr/C17 and Ph/C18 ratios is a strong indication of anthropogenic pollution. In Filippos B Port (BK sample), low concentrations of hydrocarbons and PAHs, methyl-phenanthrene and dibenzothiophene, were recorded and neither triterpanes nor hopanes were detected. Acknowledgement: This work was partially supported by the project BSB27 MONITOX.