The International Institute of Welding (IIW) acts as the global network of knowledge exchange concerning the joining of materials. One of the working teams, i.e. Committee XIII, is dedicated to new research results and the implementation of innovative technologies in order to avoid fatigue failures in welded structures. Presently, the Committee is developing several new guidelines aimed to increase the fatigue service life of welded structures. One of the guidelines concerned with the frequent use of mechanical treatment is a method of increasing the fatigue strength of welded structures. The article discusses aspects of the above-named guidelines and the unique international IIW collaboration enabling the development of these guidelines.