Conventional Portland cement is known to degrade under the attack of CO 2 . The failure is caused by formation of CaCO 3 which in the presence of wet CO 2 can leach as calcium bicarbonate Ca(HCO 3 ) 2 . This way, channels for further ingress and migration of carbon dioxide are created. Recently, a new binder system based on calcium aluminate phosphate cement has been developed which exhibits outstanding CO 2 resistance and temperature stability up to 320 °C. Main limitation of this novel binder system is a lack of additives to retard and control the water loss from the aqueous slurry.In our study, we first present an effective retarding admixture for this cement. Comparison of four different retarders (boric acid, tartaric acid, calcium lignosulfonate and butylene triamine pentamethylene phosphonic acid) revealed that only a combination of boric and tartaric acid at the specific ratio of 2.7:1 (wt./wt.) retards hydration of this cement long enough to guarantee a pumpability time of over 6 h at a pressure of 200 bars and a temperature of 80 °C.Testing of numerous fluid loss additives showed that conventional admixtures based on polyvinyl alcohol, cellulose ether or polyethylene imine do not prevent water loss. This lead to the conclusion that neither film forming additives nor synthetic polymers which physically plug cement filtercake pores will work sufficiently in this specific cement system. Thus, polymers which control fluid loss by adsorption within the pores of the filtercake were probed. This approach proved to be successful. Application of a fluid loss additive based on acrylamide tert-butylsulfonate (ATBS) produced excellent fluid loss control, even at 80 °C. The mechanism behind this performance was found to be reduction of filter cake permeability by adsorption of the high molecular weight polymer onto the positively charged surfaces of cement hydrate phases. Interaction of this admixture with the binder and its working mechanism are presented in detail.