Cosmological perturbation theory is an analytical tool to determine the dark matter power spectrum from the primordial fluctuations. However, it fails to converge at late times due to non-linear effects. In this seminar we discuss several approaches to resummation in cosmological perturbation theory. After a short introduction, standard perturbation theory (SPT), renormalized perturbation theory (RPT) and the eikonal approximation are sketched. Finally, a generalization to RPT is presented that elucidates the relation between these schemes.
