Approximately 83 tonnes × 10 6 of sulphur (mainly as SO 2 ) are released by Man into the atmosphere each year. A large part of this anthropogenically-derived sulphur eventually reaches the soil and may influence processes which are essential to soil fertility. Acid rain can have a particularly pronounced effect on soil processes, influencing in particular base status and the degree of leaching.The aim of this review is to show how sulphur in its many forms, reaches the soil, how it influences soil processes and how in turn the form of the element is altered by microbial activity.