Engineered cementitious composites (ECC) are ultra-ductile fiber-reinforced composites. The tensile strain capacity of ECC is about 200-500 times that of ordinary concrete. This ultra-ductility is a consequence to the tight multiple cracking under tensile forces resulting from incorporating random micro-fibers. This paper investigates the fresh properties of Engineered Cementitious Composites incorporating fly ash and blast furnace slag. Six ECC mortar mixes, with different fly ash and blast furnace slag ratios were tested. The flow and rheological test was used for defining the characterizations of the fresh phase. The results of the experimental test will be presented and discussed in terms of initial flowability and flowability loss.