V. V. Bolotin’s theory of fatigue-crack growth, which was based on a synthesis of fracture mechanics and the continuum mechanics of damage accumulation, is applied to delamination in structural elements made from composite materials. The delaminations considered have low rigidities compared to the main component. It is assumed that the latter is subjected to combined cyclic loading (compression with bending) and the delamination to cyclic budding under a combination of compression with bending. The distribution of the cyclic stresses on the hypothetical delamination growth path is considered within the framework of the mechanics of multilayered structures. The influence of the parameters of the material and the loading process on damage ahead of the delamination front due to microscopic separation and shearing damage is investigated. The results are presented in the form of curves of delamination growth as a function of cycle number and loading parameters.