Aim: Determine the composition of the volatile compounds in gasoline and diesel fuel using gas chromatography and, based on the data collected on the composition of gasoline and diesel fuel, use statistical analysis to check whether there is a difference in the composition of gasoline and diesel fuel depending on the supplier. Methods: The analysis was performed on 16 samples of gasoline and 16 samples of diesel fuel. The samples were taken from registered suppliers, namely 12 samples in the Republic of Croatia and 4 in Italy. The composition of volatile compounds (hydrocarbons) was analyzed by gas chromatography (GC-FID). Due to the different composition of gasoline and diesel fuels, two methods were developed for injection and analysis. Signal detection was performed by comparison with standards, and the results of the hydrocarbon composition analysis were expressed as percentage ratios. Results: Looking at the results of the statistical evaluation of the analysis of the chemical composition of diesel and gasoline fuels, two separate groups of fuels can be clearly seen. One group includes gasoline fuels from Croatian and Italian dealers, between which no significant differences in fuel composition were found. The composition of gasoline is dominated by C9, xylene and toluene, and among the other aliphatic hydrocarbons, C6 and C5 compounds showed a strong correlation. The second group includes diesel fuel from Croatian and Italian distributors. Within this group, there was a subdivision: diesel fuel from Croatian traders was combined in one group, while diesel fuel from Italian traders was separated. The peculiarity of the diesel fuels from Croatian dealers can be seen in the strong correlation of isooctane with the C10 compound, while in the Italian samples D_Es and D_Co there is a strong correlation between the aliphatic hydrocarbons C24 and C25. Conclusions: The data presented show that gas chromatography with FID detector is a good method for the analysis of liquid fuels. Due to the different composition of gasoline and diesel fuels, two methods for injection and analysis were developed in this work. The statistical analysis of the chromatographic data showed a significant separation of gasoline and diesel fuel, which was expected. The statistical analysis showed a significant separation of diesel fuel from Italian suppliers compared to Croatian suppliers, which could indicate that the diesel fuels originate from different producers.