Most grassland soils in western European countries are acidic in their natural state and require a liming material to bring them to their optimum pH. A study was conducted to determine whether Linz-Donawitz (LD) slag, a by-product of the iron and steelmaking industry, could be used as a dolomitic agent for pastures. Six rates of slag (0, 1, 1.5, 3, 5. and 7.5 t ha-'), with and without fertilizer, were investigated for their effects on soil properties, pasture yield and botanical composition, and herbage mineral concentrations. The three-year study was conducted on a newly established pasture of perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), and white clover (Trifolium repens L.), and on a resident pasture dominated by Yorkshire fog (Holcus lanatus L.) and browntop (Agrostis tenuis Sibth.). Application of slag increased soil pH (0.15 and 0.11 units per ton of slag applied at Derio and Abadiano, respectively) and decreased Al percentage of the soil complex to levels not considered harmful to plant growth. Exchangeable Ca increased markedly and exchangeable Mg slightly. In general, herbage Ca and Mg concentrations increased accordingly to their increase in the soil, while Fe, Mn, Cu, and Zn decreased with increasing rates of slag. LD slag appears to be a useful liming material for correcting soil acidity in pasture soils. and for increasing Ca and Mg, and decreasing Mn concentrations, in herbage.