Extending to continuous potentials a cleaving wall molecular dynamics simulation method recently developed for the hard-sphere system [Phys. Rev. Lett. 85, 4751 (2000)], we calculate the crystal-melt interfacial free energies, gamma, for a Lennard-Jones system as functions of both crystal orientation and temperature. At the triple point, T* = 0.617, the results are consistent with an earlier cleaving potential calculation by Broughton and Gilmer [J. Chem. Phys. 84, 5759 (1986)], however, the greater precision of the current calculation allows us to accurately determine the anisotropy of gamma. From our data we find that, at all temperatures studied, gamma(111)<γ(110)<γ(100). A comparison is made to the results from our previous hard-sphere calculation and to recent results for Ni by Asta, Hoyt, and Karma [Phys. Rev. B 66 100101(R) (2002)]. (C) 2003 American Institute of Physics.