A variable connectivity, double-rebridging Monte Carlo (MC) technique is developed for simulation of long chain molecules. The method changes the connectivity of inner segments of two chain molecules by making use of a recently proposed inner-chain rebridging scheme [Chen , J. Chem. Phys. 113, 11382 (2000)]. The new method yields results consistent with other molecular dynamics and MC methods, but it enhances considerably the rate of equilibration of chain end-to-end vectors for long molecules. The new method is tested for linear polyethylene melts at 600 K. Polyethylene is modeled as linear 200 and 1000 carbon chains, respectively, using the NERD united-atom force-field (Nath, Escobedo, and de Pablo revised united-atom force field) [Nath , J. Chem. Phys. 108, 9905 (1998); Mol. Phys. 98, 231 (2000); J. Chem. Phys. 114, 3612 (2001)]. (C) 2003 American Institute of Physics.