3D printing has been well established for prototyping of plastic parts. However, 3D printed parts usually have lower density and when combined with limited types of materials of choice, their properties differ from the real injection molded parts of the desired material. Most of the mold inserts are made from steel which is expensive and takes long building time. Thus, the quality, cost and lead time of the mold affect the economics of production, especially in the automotive industry. In this work, PolyJet 3D printing technology was applied to build the mold insert using photopolymer resin (Digital ABS). PP, PE, ABS and PA6 were materials of interest to be injected into 3D printed inserts using different conditions. The feasibility of 3D printed mold inserts to produce prototype parts was determined by the inserts’ strength, dimensional and thermal stability. It was found that the inserts’ shrinkage depended greatly on the printed dimensions. The compressive strength of the inserts reduced up to 50-54% when the temperature was increased from 23 °C to 180 °C during the injection molding resulted in slight dimensional variations of the injected prototype part compared to the cavity wall. Improving the thermal stability of the printed inserts for successful prototyping of ABS and PA6 parts could be achieved by annealing the inserts with designated conditions.