Nearly 5 million babies have been delivered following assisted conception (IVF/ICSI) and the demand is increasing. Meticulous ovarian stimulation and well programmed luteal phase support are the landmarks of treatment success. Although the importance of luteal phase support in IVF/ICSI cycles is well established, the optimal route, dose and duration of this support is still a matter of debate. Regardless of the ovarian stimulation, parenteral and vaginal progesterone has been one of the most common routes. However, oral or subcutaneous routes are also well-investigated and reveal satisfactory clinical outcomes. It is obviously critical to choose a progesterone with adequate clinical efficacy and patient tolerability as well. Moreover, fresh and frozen embryo transfer cycles markedly different from each other in terms of physiological changes and luteal support concept should be modified accordingly. The aim of this narrative review is to provide evidence-based take home messages for the luteal phase support in either fresh or frozen embryo transfer cycles in the context of a recent scientific evidence.