The properties of high performance concrete, mainly in the fresh state are governed by the flow behaviour of the paste phase, which is controlled by the dispersion of cement particles by the superplasticizer. In this paper, experimental procedures for evaluating the flow behaviour of cement paste with different types and dosages of superplasticizers are studied. The rheological nature of the paste is represented through the Bingham and Herschel-Bulkley models. It is observed that the Marsh cone flow time, mini-slump spread and the rheological parameters show the same trend with change in dosage of superplasticizer. Also, the rheological parameters increase with time and rate of increase is more significant at dosages less than the saturation dosage, as determined from the Marsh cone test. It is confirmed that the Marsh cone flow time can be predicted using an appropriate model. © 2008 RILEM.