Ball burnishing is a surface treatment process in which plastic deformation of surface irregularities occurs by exerting pressure through a very hard ball on a surface to generate a uniform and work-hardened surface. In this work, the effect of ball burnishing with different pressures (100, 200 and 300 bar) on the fatigue behaviour of AISI 1045 steel was investigated. Ball burnished specimens were cyclically deformed at room temperature using rotating bending tests and compared to the non-surface treated specimens as a reference state. As the results of fatigue tests, ball burnishing can significantly enhance both fatigue limit and fatigue life as compared to non-surface treated specimens for each pressure value of the ball burnishing while fatigue limits of specimens treated by different pressures were almost equal to each other. This improvement of fatigue behaviour may be due to near surface compressive residual stresses as well as cold hardening and increased hardness induced by mechanical surface treatment (ball burnishing).