This paper deals with the study of agronomic use of sewage sludge from sewage plants of central Spain; in order to determine the effect of thermally dried sludge in soil chemical properties of three cereal crops (barley, oats and wheat). The test was carried out in the field for 4 years. Four treatments were evaluated: control (C), mineral (M) with 300 kg / ha of a 15-15-15 fertilizer (N, P, K) and 5000 (L 1), 8000 (L 2) and 12000 (L 3) kg / ha of thermally dried sludge. The results obtained showed that sludge-amended soils undergo an increase in pH, electrical conductivity, organic matter and nitrogen content, phosphorus, calcium and magnesium. The total concentration of heavy metals, zinc, copper and nickel increase compared to control soil after four years, but there was no risk of contamination.