The supply of water is limited in some parts of the Mediterranean region, such as south-eastern Spain. For this reason strategies for saving water are necessary, especially in agriculture. The use of treated waste waters for the irrigation of agricultural land is a good solution to this problem, because it reduces the utilization of fresh water and can improve key soil parameters, thus influencing crop production in a positive way by increasing soil nutrients and organic matter content. The use of treated waste waters for irrigation is increasing, but it is not completely known if their use implies any risk for soil and human health. In this work we are studying the short-term effects of irrigation with waste waters on soil chemical properties in an agricultural area located at Biar (Alicante, Spain), with a crop of grape (Vitis labrusca). The soil parameters studied are: pH, electrical conductivity, organic matter, nitrogen, phosphorous, available K, Na, Ca, Mg and heavy metals content. Three treatments are being applied in the irrigation of the soil: fresh water (control), and treated waste waters from secondary and tertiary treatment. A soil sampling was carried out every four months. We show here the results after 1 year of irrigation treatments. Laboratory analyses confirm that at the moment only a few statistical differences have been found between treatments, and in no case do they imply a negative impact on the soil. Although we show here partial results of a long-term experiment, the conclusion is positive since treated waste waters are not producing notable changes on soil parameters compared with plots treated with fresh water. * Tel.: +34 966658948; FAX: +34 966658532. fuensanta.garcia@umh.es