Increasing marine traffic, over 55,000 ships visit per year, through the Turkish Straits System and the Sea of Marmara, produces a yearly average of 12 illegal oil discharges. This paper documents the comparison of chemical fingerprints of spilled oil with suspected sources of oils for identifying the source of illegal pollution in Turkey's seas. Fingerprinting is initiated by comparison of the synchronous fluorescence spectra (Delta=20 or 15 nm) of fugitive and suspected source oils. Potential matches of the spectra/chromatogram are confirmed or rejected by subsequent comparison of Fourier transthim infrared spectrometry (FTIR), high-pressure liquid chromatography (HPLC) and gas chromatography with a flame ionisation detector (GC-FID) analysis results, In this study, 39 clean sea waters, 41 polluted sea waters and 111 suspected samples were analysed. According to the comparison of the suspected source sample and polluted sea water sample spectra by using spectrofluorometric analysis, 76 suspected source samples were categorised as non-match whilst 35 suspected samples were classified as match or probable match. Then, match and probable match samples were analysed by using further selected chromatographic methods. Finally, 28 suspected source samples were confirmed as a match, enabling legal proceedings to be initiated.