Steroid hormones are essential regulators of the organism functions connected with reproduction, stress and metabolism. The present review gives information on steroid hormones biosynthesis pathways in members of the class Teleostei in comparison with steroidogenesis in mammals (specifically humans), as well as on the system of steroid receptors, the corticosteroid reception being presented in more detail. Uncovering of the mineralocorticoid regulation in fish is described in retrospective. Generic knowledge is given on the involvement of corticosteroids in osmoregulation in teleosts, which differs significantly from that in tetrapods. Despite the high similarity in the pathways of steroid hormones biosynthesis in bony fishes and mammals, there are some essential differences, i. e. 1) the inability of teleosts to synthesize aldosterone, 2) the ability of teleosts to synthesize maturation inducing steroids (MIS), and 3) differences in androgen biosynthesis pathways.