The scope of this chapter is to introduce the current technology for measuring the rheological properties of concrete. The need to evaluate or assess the flow properties of concrete has resulted in the invention or design and standardization of hundreds of tests methods. A very comprehensive list of these tests methods can be found in the ACI 238 document [ ]. These tests can be roughly divided in two categories: empirical tests that try to simulate actual field conditions and tests based on direct rheological measurements. In the past 20 years, there has been an effort to move away from empirical tests toward scientifically based tests methods that produce results in fundamental units. Further, numerical models have been developed to help interpret results from experiments. These numerical approaches are sophisticated enough to account for the influence of particle shape and concentration on the flow of concrete in concrete rheometers.