The Large Core Code Evaluation Working Group has been organized for the prime aim of testing and validating neutronics codes and methods for use in the analysis of large fast reactors. For the initial problem, static neutronics calculations were performed on a “representative” 1200-MW(e) liquid-metal fast breeder reactor in a two-dimensional radial geometry. The initial results representing the cooperative effort of the participants are summarized. Various codes and methods using few-group diffusion theory are intercompared. The calculational methods are in substantial agreement provided the same multigroup constants are used. This effort is to be further pursued and broadened to investigate such specific effects as sodium voiding.