Large diameter, thin walled, high mechanical resistance steel pipe has a tendency to wrinkle on the compressive side (the intrados) of the bend when it is cold bent. This dissertation describes the principal national and international design codes that apply to wrinkling resulting from pipe cold bending, and it proposes an angle at which such wrinkling occurs. The international codes prove to be conservative regarding wrinkling in bent pipe, since a wrinkle is a geometric change, which at first causes a stress concentration and susceptibility to fatigue failure. The dissertation uses the finite element method to model the formation of wrinkling and to determine stress concentration factors in these areas for internal pressure loading. The resulting factors are compared with the results found in the literature and are utilized in calculating fatigue life by means of the following methods: Mark1, Mansons universal inclinations and ASME Section VIII Division 2. In this study API X70 structural pipe with a diameter thickness (D/t) ratio varying from 20 to 100 was utilized, and modeled using Abaqus(r) software. Bends with an angle of 4°/diameter and severe wrinkling resulted, with a ratio between the peak of the wrinkle and the diameter of the pipe (d/D) of about 6.5% and a stress concentration factor nearing 1.89. The wrinkled pipe models did not reveal any lack of mechanical resistance to the applied internal pressure when it is sufficient for obtaining a nominal circumferential stress equivalent to 100% of the yielding limit of the material. The fatigue life results for the different methods varied according to the method that was utilized, but all displayed a reduction in pipe life if there was severe wrinkling. The study proposes a conservative procedure to be utilized for calculating fatigue life. This procedure associates the stress concentration factor determined by Rosenfeld with the method for calculating fatigue recommended by the ASME VIII code. Furthermore, the study suggests that new analyses may be performed in order to consider the Bauschinger effect and the model bend instability, which the study did not evaluated.