Abstract In this study, HELIOS-2 deterministic transport code and Serpent Monte–Carlo (MC) reactor physics code were considered as tools for preparation of few-group constants for sodium cooled fast reactor (SFR) analysis. Initially, applicability of the mainly LWR-oriented HELIOS-2 code to the modeling of SFR lattices was investigated and recommendations for methodological modifications were given. At the next stage the methodology for few-group cross section generation for fuel and non-multiplying regions of SFR core was proposed. Afterward, few-group constants produced by HELIOS-2 and Serpent employing the proposed methodology were used by nodal diffusion code DYN3D for the analysis of a reference SFR core. Finally, the DYN3D results were verified against the full core Serpent MC solution. The full core DYN3D results obtained using few-group constants produced by Serpent agreed very well with that of the reference full core MC simulations. The use of HELIOS-2 based few-group constants led to somewhat reduced agreement between reference MC and DYN3D results. The implementation of the suggested modifications to the HELIOS-2 methodology can potentially improve its modeling accuracy for SFR lattices.