This paper describes the effect of curing conditions on the mechanical properties of mortars containing superabsorbent polymers (SAP). Curing temperature and relative humidity were varied from 20 to 40 degrees C and 30 to 95%, respectively, in mixes with different water/cement and cement/aggregate ratios. Tensile and compressive strength tests were performed at several ages. Weight loss over time was measured and related to curing conditions and strength. The addition of SAPs was found to effectively maintain cement-based mortar strength under extreme curing conditions.