We present a new equation of state for Lennard-Jones (LJ) flexible ring fluids. We perform Monte-Carlo simulations for freely-jointed Lennard-Jones chain fluids (3-, 6- and 8-mer) in the canonical ensemble and obtain the intramolecular end-to-end pair correlation function data under extensive density and temperature conditions. We correlate these as a function of the density, the temperature and the number of segments in a chain. We apply this function to thermodynamic perturbation theory (TPT) and obtain a new equation of state for Lennard-Jones flexible ring fluids. We also compare existing simulation data [J. Chem. Phys. 104 (1996) 1729] with the results obtained using the newly derived equation of state. (C) 2004 Elsevier B.V. All rights reserved.