<p>A study is presented on the hydrocarbon composition of four samples of the main diesel fuel fractions using GC/MS, nuclear magnetic resonance as well as ultraviolet and visible absorption spectroscopy. The analytical results revealed differences in the qualitative and quantitative composition of the hydrocarbons, which decisively affect the low-temperature characteristics of diesel fuels. The experimental data were treated by correlation analysis and the correlation coefficients were calculated showing direct and inverse relationships of the low-temperature characteristics with the content of the different hydrocarbon groups. The factors with a positive effect on the low-temperature properties were found to be high contents of low-molecular-weight C₉-C₁₅ n-alkanes and naphthenes as well as low contents of high-molecular-weight C₂₂₊ n-paraffins and arenes. Among the arenes, the greatest negative effect was found for alkyl-substituted naphthalenic and phenanthrenic hydrocarbons.</p>