Abstract Research in the past two decades on epithermal gold and silver deposits has led to the recognition of three principal varieties—volcanic-rock-related adularia-sericite(illite) type, alunite-kaolinite ± pyrophyllite type, and sedimentary-rock-hosted Carlin-type deposits. A review of the salient characteristics of each variety and the state of our understanding about the genesis is best accomplished through well-studied examples. Creede, Colorado, Bodie, California (adularia-sericite(illite) types), and Summitville, Colorado (alunite-kaolinite ± pyrophyllite type), illustrate the tectonic setting, alteration and mineralization, and environment of ore deposition of volcanic-rock-related systems. Carlin, Getchell, and Jerritt Canyon, Nevada, serve as good examples of the same characteristics in sedimentary-rock-hosted Carlin-type systems. There are many similarities among the different varieties of epithermal deposits including the predominance of a meteoric water component throughout the ore-forming stages in the volcanic-rock-related systems and in the intermediate to later stages of the Carlin-type systems; the predominance of large-scale, near-neutral pH alteration assemblages in the deeper parts of the hydrothermal systems; and the time-space relations which indicate heat energy input from intrusive rocks at differing levels in both the volcanic-rock and Carlin-type systems. The above factors allow a common genetic framework to be established for epithermal deposits. The general model involves interaction of deeply penetrating ground waters and magmatic vapor derived from contemporaneous intrusions. In the large-scale systems responsible for Carlin-type deposits, connate brines also play an important role. The transport capability of deep fluids in epithermal hydrothermal systems may be shown to be dependent largely on the H 2 S content of the deep fluid, and in turn, through a series of fluid-mineral equilibria to depend strongly on temperature and inversely on CO 2 content. Both factors relate to the source strength of magmatic or other evolved fluid at depth in the convection systems. This same common geochemical and hydrodynamic framework provides a basis for the discussion of depositional regimes and the real distinctions between the types of epithermal deposits observed in the field.