This paper presents a method to predict the fracture toughness KIc and/or KId of steels using their Charpy impact test results and tensile properties. The fracture toughness, Charpy impact and tensile properties of 21/4Cr-1Mo, ASTM A508 Cl.1, A508 Cl.2, A508 Cl.3 and A533 Gr.B Cl.1 steels were measured and analysed on the basis of the excess temperature (test temperature minus FATT) and Rolfe-Novak correlation. The relationship between KIc/KIc-us and the excess temperature, where KIc-us is the upper-shelf fracture toughness KIc predicted by Rolfe-Novak correlation, discloses that the KIc transition curves of several steels are representable by only one trend curve of KIc/KIc-us or KId/KId-us versus excess temperature relation. This curve is denoted as a “master curve”. By using this curve, the fracture toughness of steel can be predicted using Charpy impact and tensile test results. By taking account of the scattering of both the fracture toughness and Charpy impact test results, the confidence limits of the master curve were also determined. Another approach to develop more general procedure of predicting the fracture toughness KIc is also discussed.