Abstract: During the last decades the environmental concern of society has experienced an increase. Specific tools like the Life Cycle Assessment (LCA), and software and databases to apply this method have been developed to calculate the environmental burden of products or processes very diverse. Global plastics production rose to 288 million tonnes in 2012. Among the different ways of plastics processing the injection molding process is one of the most used in the industry worldwide. In this paper an analysis of the influence of the polymer in the environmental impact of the injection molding process has been carried out. In order to perform this study, the EcoInvent database inventory considered and the data from which this database is obtained for this process have been studied. In general, when a LCA of a product is carried out, databases such EcoInvent, where materials, processes and transports are characterized providing average values, are used. This approach can be good enough for some cases but in order to assess a specific process, like the injection molding process, a further level of detail is needed. This study shows how the final results of environmental impact differ significantly when modifying the generic dataset's values, using the PVC's, PP's or PET's original report data or more updated values. This aspect suggest the necessity of studying, in a more precise way, this process to evaluate its environmental burden correctly so the priority areas can be properly identified and thereby actions to develop a more sustainable way of manufacturing can be determined.