This research was conducted to determine the effect of various wastewater sludge (domestic type (B), mixture of industry and domestic type (L), aerobic food industry (P), anaerobic food industry (M)) levels on the properties of sandy soil, including pH, electrical conductivity (EC), and the levels of available N (NH4 and NO3) and P, diethylenetriamine pentaaceticacid (DTPA)-extractable microelements and heavy metals. An incubation experiment was performed in which sludges were applied at rates of 0, 40, 80, 120, and 160 tons ha(-1), and the effects on the soil properties were measured over a period of 150 days. Soil pH decreased and electrical conductivity increased with increasing levels of sludge application. The levels of NH4-N, NO3-N, available P, and DTPA-extractable heavy metals also increased with the application rate of the sludge. NO3-N content increased and NH4-N content decreased over time. The most unfavorable effects on soil properties were observed with the B sludge. Other soil characteristics changed according to the sludge properties.