Surfaces of plastic parts often need a pre-treatment before they can be further bonded or painted. Speacially the hydrophobic polyolefins are know for its difficulties in surface decoration. Since 80 % of plastic packaging are made of polyolefins, the growing requirements for cost effectiveness, appealing of decors and to use water-based paints have created a challenging situation. In the presented project an innovative method of process-integrated surface decoration of polyolefins has been investigated. Using this In-Mold Printing technology, fully finished surface decorated parts can be produced during injection molding without any additional materials, like carrier foils. Here two subsequent processing steps are saved compared to the common printing process of polymer parts: the surface modification for better adhesion and the printing itself are integrated in the process of injection molding. This could be realized by printing patterns of modified paint on the mold surface, e.g. by pad printing. During injection molding the paint is transferred completely to the surface of the polymeric part, which develops at this point. In-Mold Printing shortens the process chain, saves material, energy, time, transport, handling and fault probability and opens new application fields, e.g. the integration of printed electronics to low-cost plastic products in mass-production.