This paper presents a description of the lattice physics code LANCER02, developed for use on boiling water reactor fuel designs at Global Nuclear Fuel and General Electric Energy, Nuclear. Included in the paper is a detailed description of the methodology used to determine the neutron flux distribution throughout the problem. The paper focuses on single-assembly analysis as well as multibundle analysis along a plane of a reactor core. A small sampling of results from the lattice physics code are compared against results generated by continuous-energy Monte Carlo analysis.