The endogenous steroid 2-methoxyestradiol (2-ME) is a metabolite of 17β-estradiol and its biosynthesis is well established. Moreover, 2-ME is also biosynthesized from estrone. For several years, 2-ME was perceived as an inactive metabolite devoid of any interesting biological activities. Since the late 1980s, a number of biological and pharmacological studies have revealed that 2-ME possesses interesting anti-cancer effects without any undesirable estrogen activity. In particular, the anti-vascular effects and anti-angiogenic activities that 2-ME exhibit, are of great interest and importance, in view of the development of new anti-cancer drugs based on 2-ME. Several clinical trial development programs have been initiated using the steroid 2-ME. In addition, based on the many pharmacological activities reported for 2-ME, but also due to the general interest in total and semi-synthesis of endogenous steroids, several research groups working with organic synthesis have prepared this steroid. Herein, the anti-cancer effects, the results from the clinical trial development programs and the synthetic studies towards 2-ME, are reviewed.