In recent years, the different methods of stacking of the blade profiles from hub to the tip are studied frequently for axial fans and compressors. The blade profiles can be stacked on a radial line where the centers of gravity of the profiles coincide or the blade shape can be obtained by shifting the profiles in axial direction or in other directions (parallel or perpendicular to the chord line of the profile). In this manner, it is possible to make a modification on the 3D flow structure without making any change on the angle of the profile on 2D plane. In this study, the effect of the leading edge shape (related to the stacking process) on the performance and on the 3D flow structure of an axial fan rotor is handled. First, a reference fan where the centers of the gravity of the profiles situate on the radial stacking line is designed. This fan is optimized by means of CFD tools to give the maximum efficiency. The results of the CFD calculations are validated by experiments. Subsequently, new fans are obtained by shifting the profiles in axial direction to give the desired leading edge shape. The performances and the flow structures of the new fans are investigated and compared by means of CFD calculations. The CFD results show that, neither convex nor concave leading edge has positive effects on the aerodynamic performance of the axial fan studied. However, some potential advantages of the new geometries are observed especially at the hub and the tip region of the fans which are aerodynamically the most problematic regions of an axial turbomachine.