The open source tools for modeling the processes of fluid dynamics and heat transfer and the possibilities of their application for the problems of foundry are considered. OpenFOAM, Elmer, ParaView and Salome Platform were selected as the main potential competitors for commercial casting simulators. The results of experimental calculations of casting processes using open source software are presented. The results of research on publications and the authors’ own experience in the use of free software in foundry are highlighted.