An experimental program aimed at determining ultra-high performance fiber-reinforced concrete (UHPFRC) uniaxial compressive behaviors was conducted. Overall stress-strain behavior, strain capacity, modulus of elasticity, and strength of both steam-treated and untreated UHPFRC were determined by analyzing results of compression tested cylinders. Enhanced stiffness and exceptional compressive strength were exhibited by UHPFRC according to study results. The authors present modulus of elasticity as compression strength function and strength gain with time predictor equations. The authors present UHPFRC stress-strain response linearity and establish an ascending branch compressive stress-strain behavior equation.