Reactive molding process of thermosetting materials is an area where advanced computer simulations can provide useful information to detect molding problems prior to the mold making. Examples of such problems are premature gelation, undesired weld-line locations, and air traps, However there is a lack of suitable software that would allow the modeling in a fully three-dimensional (3-D) space for such reactive systems. A new approach for the 3-D simulation of reactive molding process is presented in the paper. In the filling stage fluid dynamics and heat transfer are modeled within a system of resin and a mold, combined with appropriate viscosity and curing reaction models. During the curing phase only heat transfer and curing kinetics are taken into account. The presented approach was verified by comparing computational results for a cylindrical test to experimental measurements and was successfully applied on a real industrial process in manufacturing of a medium voltage combi sensor. The selected results of such simulations are also presented in the paper. (C) 2003 Wiley Periodicals, Inc.