Molecular dynamics simulation is one of the most useful methods to model defect generation and subsequent change in mechanical properties in material that will suffer irradiation in the future fusion reactors. This work is aimed at showing the influence of the empirical interatomic potential for the Fe–Fe interaction on the simulated shearing of α-Fe containing one edge dislocation interacting with one nanometric void sitting on its glide plane. The recent potentials derived by Ackland et al. [G.J. Ackland, D.J. Bacon, A.F. Calder, T. Harry, Philosophical magazine a-physics of condensed matter structure defects and mechanical properties 75 (1997) 713], Mendelev et al. [M.I. Mendelev, S. Han, D.J. Srolovitz, G.J. Ackland, D.Y. Sun, M. Asta, Philos. Mag. 83 (2003) 3977] and Dudarev–Derlet [S.L. Dudarev, P.M. Derlet, J. Phys. Condens. Matter 17 (2005) 7097] are used to identify critical parameters. The stress–strain responses are obtained under imposed strain rate and at temperatures ranging from 10 to 700 K at constant volume. It appears that different potentials give different strengths and rates of decrease of obstacle strength with increasing temperature. Results are analyzed in terms of dislocation core structure and thermal expansion. Implications for the choice of the potential are given.