One of the effect of temperature decreasing on alloy steels is the change of ductile behavior in a fragile one. The influence of the temperature on breaking nature has a considerable importance. Many steels exhibit ductile fracture at elevated temperatures and brittle fracture at low temperatures. The temperature above a material is ductile and below is brittle is known as the transition ductile - brittle temperature, also known as Nil-Ductility Transition (NDT) temperature. This temperature is not precise, varying with the thermal and mechanical treatment applied in advance, and the nature and amount of impurities. NDT is determined according to the standards, using Charpy test. This paper aims to increase the accuracy of the transition ductile - brittle temperature determination, by correlating information from impact bending test with those obtained by the fatigue test.