This paper presents the results of a numerical investigation focused on the influence of pre-chamber geometry, specifically, the number and diameter of orifices – on hydrogen combus-tion characteristics in a Turbulent Jet Ignition (TJI) system. Computational Fluid Dynamics (CFD) simulations were conducted using AVL FIRE software in two configurations. In the first case, the number of orifices was varied while maintaining a constant diameter, whereas in the second case, the orifice diameter was adjusted to preserve an equivalent total flow cross-sectional area. The obtained results indicate that both geometrical parameters significantly affect the combustion behavior, particularly in terms of mixture stratification, pressure distribution within the main combustion chamber, and nitrogen oxide (NO) formation. It was determined that the number of orifices exerts a more pronounced effect on combustion per-formance than their individual diameter. An increased number of orifices with a diameter of 1.5 mm enhanced system efficiency due to improved flow penetration and jet momentum. Under the condition of a constant total discharge area, the configuration comprising five ori-fices with a diameter of approximately 1.34 mm yielded the most favorable results. This con-figuration ensured stable combustion operation with respect to the analyzed performance and emission parameters.