The maturity function provides a reliable approach in the determination of the in situ strength of concrete at later ages. This study was aimed at determining the strength-maturity relationship on concrete specimens which were prepared using different admixtures and cured under different temperatures. For this reason, three sets of concrete specimens, having dimensions of 15 X 15 X 15 cm, were produced using the set accelerating admixture, set retarding admixture, and no admixture content at a constant consistency and 0.59 water-to-cement ratio. All hardened concrete specimens were cured at 0, 20, and 40 degrees C temperatures under 100% humidity for 1, 3, 7, and 28 days. The compression tests were applied on specimens at the end of the curing time. Equations for the relationship between maturity and strength were worked out for the admixtures used in the study.