In this article, theoretical and experimental results for the chemical autoignition delay time of the homogeneous combustion compression ignition (HCCI) combustion mode with diesel fuel are presented. These results allow a further analysis of the chemical kinetic mechanisms that control the fuel oxidation in HCCI internal combustion engines. The CHEMKIN software, in conjunction with a one-zone model, has been used to compute the autoignition delay time for different engine performance parameters. The numerical results have been validated with experimental results obtained in a diesel engine adapted to HCCI combustion. Finally, the numerical model has been used to analyze different engine parameters such as fuel composition, intake temperature, exhaust gas recirculation (EGR), fuel air/ratio, and engine speed.