The residual stresses were proven to play a relevant role in the fatigue life expectations of components and specimens. It is well established that almost every manufacturing process to some extent leads to the residual or internal stress fields formation. The challenge is to properly account for these internal stress fields in the fatigue life prediction. In this essay a comprehensive study of the mechanical fatigue subject is presented, with particular focus on the residual stresses issue, as their impact on the fatigue life expectations, the manufacturing processes behind their formation, their measurement methods and the most preforming way to account them in the fatigue life estimates.