This thesis explores the orientation effect of notch toughness caused by the forging fibre in large forgings. In the literature part of the thesis the term forging fibre and the influencing variables on it are defined. Base product for the experimental part was a continuous cast steel block measured 150 x 150 mm. It was forged with a hydraulic press. V-notch specimens were produced out of the material of reference and the forged specimens in various orientations. The V-notch tests were executed in a range of temperature from -40 °C to 140 °C. The testing results show a significant difference in the behaviour of notch-toughness between the forged specimens and the material of reference. Generally, the ductile-to-brittle curve of the forged specimens always marked a higher notch-toughness and lower transition temperature than the material of reference. Due to the size effects of the defects and the limited sample size for each testing-temperature a certain variance of the results is given. The orientation dependence of the V-notch toughness among the forged specimens did not vary distinctively. It has to be noted that for a more specified statement, a testing series with a significantly higher sample size is required.