With silver-110 m as a tracer, detailed investigations were carried out on the adsorption of silver on freshly prepared hydrous ferric oxide in the pH region 4–8, and silver equilibrium concentration range 10−4–102 p.p.m. The results fit Freundlich adsorption isotherms, and may be explained in terms of hydrogen–silver ion exchange. They also show that adsorption is essentially complete in less than 5 min and is strongly dependent on pH and the manner in which the precipitate was prepared, but is independent of temperature in the 0–50 °C range, of moderate concentrations of sodium nitrate (~10 g/l), and of trace concentrations of sodium chloride [Formula: see text] during test periods ranging from 1 to 3 days.Tests also showed that under equilibrium conditions and similar chemical environments the amounts of silver coprecipitated or adsorbed were identical.