One of the prominent features of Antarctic soils, and one which shows their relationship with soils in other arid regions of the world, is the high content of soluble salts. These salts consist largely of the sulfates, chlorides and nitrates of Na K, Mg, and Ca. Almost all possible crystalline phases formed by combination of these anions and cations are found. The origin of these salts has been a matter of controversy for many years. Various origins are postulated, including chemical weathering of rocks, deposition of marine salts and leaching from sedimentary rocks. Soils sampled along the length of the Trans-Antarctic Mountains during the last 17 yr are formed from a wide range of soil parent materials, under significantly different climatic conditions and age of weathering surface. From the relationship between these factors and the nature of the salts found in the soils, soil pH and the distribution of calcite crusts, it is possible to show that the greater part of the salt is derived from marine salts, although there are significant contributions from chemical weathering processes. The chemistry of the salts shows that chemical weathering takes place in Antarctic soils, even in the coldest and most arid regions of the Trans-Antarctic Mountains.