Results of geopolymer cement tests in saline water curing are reported. Saline water exposed curing is relevant to wellbore cements used for geo-sequestration of CO2 in saline aquifer. The conventional Portland cement based oil well cements have unfavourable results when cured in saline water. However, geopolymer based cements cured in saline water showed higher strength results than the ones cured in normal water. The reason for this behaviour is not readily apparent, and hence microstructure investigations, namely, scanning electron microscopy, Energy-dispersive X-ray spectroscopy and X-ray diffraction were performed. Saline water cured geopolymer samples also were found to have lower sorptivity test results than normal water cured samples. Improved properties of geopolymers when cured in saline water is found to be related to reduced leaching of reactants from the samples rather than the result of ingress of saline water into the samples. Geopolymers tested are made from fly ash with small amount of slag (9%), and were cured at room temperature. (c) 2013 Elsevier Ltd. All rights reserved.