The ballistic transport performance of field-effect transistor (FET) based on hydrogenated silicene and germanene, i.e., silicane and germanane, respectively, is examined. The electronic band structures of silicane and germanane are investigated using the first-principles density functional theory. Subsequently, the ballistic performance of FETs is evaluated via the semiclassical ballistic transport model. We find that silicane n-MOSFET offers a relatively better ON-current performance than transistors made of germanane and 2-D transition metal dichalcogenides (2-D-TMDs) (MoS ₂ , MoSe ₂ , WS ₂ , and WSe ₂ ). Germanane n-MOSFET suffers from the issue of low density of states due to its smaller electron effective mass. P-FETs based on germanane and silicane have higher ON-current than those of 2-D-TMDs p-FETs. Further investigation on other aspects of silicane and germanane MOSFETs, such as gate leakage and contact resistance, is needed to comprehensively assess their overall performance metrics.