In this special issue of Minireviews in Medicinal Chemistry, called Beyond Reproductive Effects of Sex Steroids, the reader will find representative papers of the state of the art in the field of non-reproductive effects of sex steroids. For instance, Terán-Pérez and co-workers discuss the role of steroid hormones in the sleep-waking cycle. Cabrera-Muñoz et al., review the role of estradiol and progesterone in the susceptibility and disease progression of one of the most important health problems on the last decade: HIV infection. Furthermore, González-Arenas and Agramonte-Hevia make a review on the effects that sex steroid hormones have on normal and pathologic conditions of the lung. The effects of sex steroids on the maternal brain is very nicely reviewed by Kinsley et al. The role of sex steroid hormones in immunoregulation, particularly in the establishment, growth and reproduction of parasites is reviewed by Hernández-Bello et al. De Nicola et al., make an interesting contribution regarding the role of estradiol in neuroprotection during hypertensive encephalopathy. The regulation of morphological and functional characteristics of the amygdala regulated by sex steroids in the adult rat is a topic boarded by Rasia-Filho and co-workers. Finally, Bautista et al., talk about the role of sex steroid hormones in one of the most important functions of organisms: appetitive behavior. We hope that our readers will find fascinating this Special Issue devoted to the wide non-typical functions in vertebrates.