© 2020 fib. International Federation for Structural ConcreteThere are many studies related to the fresh state properties of the cementitious systems in the literature. However, there is no specific study about the effects of false set formation on fresh state properties of these systems. In this study, the effect of false set formation on fresh state and rheological properties of the cement paste mixtures containing high range water reducing (HRWR) admixture was investigated experimentally. For this aim, two different commercial CEMI 42.5 R. type cements produced by different companies were used. In order to investigate the effect of false set formation related anomalies on fresh state properties, paste mixtures were prepared with different mixing times. In the mixtures where false set related anomaly was the case, rheological properties were positively affected by prolonging the mixing time.