Carbon fibre reinforced plastics offer various options to improve structures made from conventional materials such as metal. Carbon fibre reinforced plastics are used increasingly in various sectors such as the aerospace, automotive or sports industry. As carbon fibre reinforced plastics are less damage tolerant as metals due to the brittle epoxy resin matrix, this project dealt with improving the damage tolerance of the CFRP-steel hybrid structures. An extensive literature review highlights the possible toughening mechanisms of epoxy resin matrices by using additives made from polymeric and inorganic materials. Furthermore, the manufacturing process resin transfer moulding, but also potential test setups were researched. Apart from toughening the matrix, the interface between the carbon fibre body and a thin steel sheet attached on top of the specimen was researched as well. For that, different interface materials such as short fibre veils, weaves and polymeric materials were reviewed. Based on the literature review a hypothesis was defined. Increasing additive concentrations, which were core-shell rubber particles and silica nanoparticles in particular, should yield an increasing impact performance. However, the influence of the manufacturing process and its limitations had to be considered as well. Furthermore, the influence of different interface materials can improve the bond strength of metal-CFRP hybrid structures. All test specimens were produced with resin transfer moulding. The matrix toughening was researched by doing an impact testing series, which was analysed with microscopy, ultrasonic testing and differential scanning calorimetry. A variety of different additive combinations were included in impact specimens. An air pressured impact cannon was used to impact the specimens. For the interface toughening, a mandrel peel test setup was developed to compare the required peel forces for different interface materials.