Sandblasting is a procedure of increasing surface roughness. This treatment is common in the orthopedic field. An increased roughness may affect the endurance limit of the material. This study investigates the effect on the endurance limit of the Ti6Al4V due to two different sandblasting treatments: fine sandblasting and coarse sandblasting. Twenty hip stems, 10 finely sandblasted and 10 coarsely sandblasted, were tested under sinusoidal fluctuating bending. The staircase method was used to estimate the endurance limit of the material. The results show an important reduction in the endurance properties up to 40% for the coarsely sandblasted specimens. The failures of the sandblasted specimens were not due to material defects. Rather, the decreased endurance strength of the sandblasted stems was caused by surface defects, which act as crack initiators. By modulating the roughness with an appropriate sandblasting treatment, it is possible to limit the reduction in the endurance limit of the alloy.