The sorption behavior of two lignosulfonates onto two different cements was investigated via GPC and ultraviolet spectroscopy.Rapid sorption occurred and more than 80% of the added lignosulfonate were consumed by cement within the first five minutes of hydration.While similar amounts of lignosulfonate were consumed by both cements, it was found that the cement composition had significant impact on the hydration of cement paste and the cement paste flow resistance.The initial hydration curves suggest that lignosulfonate modifies dissolution of both C3A and C3S.Changes observed in the initial hydration curve induce additional changes in the main hydration curve where the lignosulfonates either retard hydration of the C3S phase or no retardation is observed in a particular case.Cement pastes prepared from the cement with low amounts of C3A exhibited "normal" features while cement pastes prepared with a cement with high C3A content set rapidly in the presence of the lignosulfonate with high molecular weight and low charge density.In contrast, fluidity was maintained with the low molecular weight lignosulfonate with high charge density.These features are suggested linked to the lignosulfonate interaction with the different cement minerals.