In order to assess the suitability of sludge application for maize (Zea mays L.) soil ecosystems, this study aimed to evaluate soil microbial properties over three consecutive years using treated municipal sewage sludge (TSS) amendment in the Typic Xerofluvent Mediterranean soils of Turkey. Soil microbial properties and biochemical activities significantly increased with increasing TSS amounts. Microbial biomass carbon peaked following amendment with 30 Mg ha(-1) a(-1) of TSS, while basal soil respiration was not significantly affected by TSS doses. Moreover, soil enzyme activity increased significantly with increasing TSS amounts. A significant increase in the grain yield of 7% and 9% was found with 10 and 20 Mg TSS ha(-1) a(-1) applications respectively, whereas a significant decrease of 5% was found with 30 Mg TSS ha(-1) a(-1). Our results suggest that if the goal is to achieve plant yield in the short-term, it seems that TSS application of 20 Mg ha(-1) a(-1) can be recommended as organic fertilizer without causing potential risks. On the other hand, if the primary aim is to ensure the sustainability of the soil organic matter, the use of TSS as organic soil conditioner at a rate of 30 Mg ha(-1) a(-1) can be recommended.