Friction as well as adhesion hinder the demolding of injection molded parts. Both are influenced by the polymer and the steel mold surfaces. A practical relevant test device, built as friction tester integrated into an injection mold, enables the analysis of demolding forces and friction coefficients under real injection molding conditions. Four low-viscous polypropylene grades (PP), one polyoxymethylene grade (POM) and 2 thermoplastic elastomers were analyzed in combination with various mold surface structures, mold temperatures and normal force levels. The static coefficient of friction µ0 was calculated as the quotient of maximum measured demolding force and acting normal force. Increasing normal forces rise the necessary demolding forces for all polymers examined. However, higher mold temperature as well as surface roughness reduce the demolding forces in most cases. The lowest coefficients of static friction (µ0 = 0.02 to 0.11) were detected for POM and a DLC-Flex coated mold surface (Ra = 0.059 µm) at a mold temperature of 80°C.