A finite element-boundary element hybrid method has been developed for one or two group neutron diffusion calculations. A linear or bilinear finite element formulation for the reactor core and a linear boundary element technique for the reflector which are combined through interface continuity conditions constitute the basis of the developed method. The present formulation is restricted to two-dimensional geometries and has been implemented in the developed computer program. Via comparisons with analytical solutions, the proposed method has been validated. Further comparisons against the pure finite and boundary element formulations show that the proposed method constitutes a viable alternative for the numerical solution of neutron diffusion problems of both the external neutron source and multiplication eigenvalue determination variety. (C) 2004 Elsevier Ltd. All rights reserved.