A modification is made with regard to the thermal group treatment of Borresen’s coarse-mesh method by using the nodal interface flux obtained from an analytical procedure as well as the nodedependent thermal group weight factors for the enumeration of the node average thermal group flux. From the numerical studies of the three-dimensional International Atomic Energy Agency benchmark problem, it is shown that the modification results in an improved accuracy in the gross power computation of the three-dimensional pressurized water reactor problem.