This study investigates the mechanical properties of ultra-high-performance fiber reinforced concrete (UHPFRC), considering various prominent factors to obtain fundamental details of its practical use. Therefore, this paper aims to review the mechanical properties of hardened UHPFRC. The influence of the curing regimes, coarse aggregate, mineral admixtures, fiber properties, specimen size, and strain-rate on the mechanical performance of UHPFRC were specifically investigated in its hardened state. It was clear that (a) hydration process is accelerated by the heat treatment which leads to higher strength; (b) fly ash, slag and rice husk ash can be used by replacing a portion of the silica fume as mechanical perspective is concerned; (c) at a static rate the use of deformed (hooked and twisted) or long straight steel fibers enhance the mechanical properties; and (d) mechanical properties are increased when the strain rate is increased. Alternatively, there are some dissent between the results from various ‘size effect’ tests and the potency of using twisted steel fibers at static and high rate loadings.