When designing machine and equipment components, one of the requirements is to ensure sufficient durability of these components. A process that increases the strength and fatigue life (FL) of machine components is ball burnishing. The subject of the research were of C45 steel samples, which were subjected to a ball burnishing (BB). The samples were pre-ground and then burnished using the following parameters: force F = 400 N, burnishing feed f = 0.1 mm/rev. and speed vb = 0.62 m/min. As a result of BB, the surface topography changed in relation to the pre-treatment. The 3D surface roughness parameters are lower, with a maximum reduction of 82%. After BB, an increase in microhardness was achieved, with a hardened layer thickness of 50 μm. Compressive residual stresses (CRS) occur in the surface layer after BB, whose were 202% greater than after pretreatment. The fatigue life of ball burnished samples is 13% higher for oil than for air, and 8% higher for ground samples. The use of oil as a medium for fatigue testing limits crack propagation.