In this work, the evaluation of the durability to wet/dry cycling exposure of cement composites reinforced with nanofibrillated cellulose comparing the results with composites reinforced with conventional cellulose fibres at the micro-scale level has been performed. For this purpose, cement mortar composites reinforced with cellulose fibres from conventional sisal pulp and cellulose nanofibres prepared by the application of a high intensity refining process have been prepared. The mechanical performance of the composites prepared was tested after 7 days of cure treatment and after 5 wet/dry cycles. The cement mortar composites reinforced with the nanofibrillated cellulose exhibited higher flexural strenght and flexural modulus but lover values of fracture energy than the ones reinforced with the conventional sisal fibres. No significant improvements of the durability were found for the composites prepared with nanofibrillated cellulose