The growth and melting of iron nanoparticles in liquid iron have been investigated as functions of particle size and temperature by a classical molecular dynamics simulation. The bifurcation radius, demarcating the growth or melting of a nanoparticle in liquid iron, decreases with decreasing temperature. This corresponds to a depression of the melting point with decreasing particle size. The depression of the melting point is proportional to the inverse of the initial radius of the nanoparticle in liquid iron, and is due to the Gibbs-Thomson effect. (C) 2009 Elsevier B. V. All rights reserved.