This paper is part of the larger study on the application of superabsorbent polymers (SAP) in concrete construction. The focus here is placed on the assessment of SAP efficiency as an internal curing agent in cementitious materials with blended cements. The paper presents the outcomes of two experimental studies on polymer modified mortars containing ground granulated blast-furnace slag (GGBS) and fly ash (FA). Results show that SAP has a positive influence on mortars with blended cements due to its capacity to release water for longer periods. Any SAP addition will result in significant reductions in autogenous shrinkage. Long term compressive strength values of SAP modified mortars are comparable with the reference specimens despite an initial drop due to polymer collapse. The use of SAPs in blended cements meets the challenges of the construction industry to produce new composites with improved performance.