Investigations were previously performed about the effect of high temperature prestraining on the notch toughness and the characteristics of fracture stress curves of various structural steels. In this report, similar studies were carried out on several weld metals, deposited by manual arc welding or submerged-arc method. As the results of the tests on these deposited metals, the following were concluded. (1) The effects of high temperature prestraining on the notch toughness were generally more remarkable than those for rolled steels. The most harmful prestraining temperature was about 200-300°C, which was the same for rolled steels. (2) The prestraining by 10% at 200-300°C elevated mainly the left half of the fibrous fracture stress curve, or shortened the distance between both fracture stress curves, cleavage and fibrous. Such test results might correspond to the remarkable rise of transition temperature in V-Charpy test after such treatment. (3) A good relationship was also found to the deposited weld metals as well as to the rolled steels, between the heights of both fracture stress curves and transition temperatures in V-Charpy test (see Fig. 15).