Multiscale modeling, including molecular dynamics (MD) and discrete dislocation dynamics (DDD) methods, appears as a significant tool for the description of plasticity and mechanical properties of materials. This research concerns the influence of irradiation on the plasticity of pure Fe and focuses on the interaction of a single dislocation with a spherical void at various geometries. MD simulation shows that the void strengthening is proportional to the interaction area. Stress field around the void influences also the dislocation passage. DDD calculation coupled to finite element method (FEM) is used to simulate the interaction of an edge dislocation with a void. DDD calculations present a good match to the MD simulation results at the near-atomic scale. They highlight the impact of image forces on the dislocation due to the free internal surface of the void and the one of its surrounding stress field. (C) 2008 Elsevier B.V. All rights reserved.