In this study, some durability properties of alkali-activated slag (geopolymer) mortars were investigated. In determining these durability properties, a series of test procedures such as high temperature, abrasion, rapid chloride permeability and wetting and drying cycles were performed. For the slag activation, sodium metasilicate was used at three sodium concentrations, 4%, 8% and 12% by mass of slag. Prismatic specimens with 40 x 40 x 160 mm dimensions were prepared from geopolymer mortars for the tests. After 24 h, the specimens were demolded and cured in three different ways until the test time: curing in an oven at 75 degrees C for 1 day, curing in air for 28 days and curing in water at 22 +/- 1 degrees C. The results obtained from the tests were compared with the control mortar made with ordinary Portland cement (OPC).The findings revealed that the resistance of alkali-activated slag mortars under aggressive media investigated within the scope of this work was higher than that of OPC mortar.