In this study, comprehensive two dimension gas chromatography (2D GC-MS) and 15 T Fourier transform ion cyclotron resonance mass spectrometry (15T FT-ICR MS) connected to atmospheric pressure photo ionization (APPI) have been combined to obtain detailed chemical composition of a diesel oil sample. With 2D GC-MS, compounds with aliphatic alkyl, saturated cyclic ring(s), and one aromatic ring structures were mainly identified. Sensitivity toward aromatic compounds with more than two aromatic rings was low with 2D GC-MS. In contrast, aromatic compounds containing up to four benzene rings were identified by APPI FT-ICR MS. Relatively smaller abundance of cyclic ring compounds were found but no aliphatic alkyl compounds were observed by APPI FT-ICR MS. The data presented in this study clearly shows that 2D GC-MS and 15T FT-ICR MS provides different aspect of an oil sample and hence they have to be considered as complementary techniques to each other for more complete understanding of oil samples.