The knowledge of the diffusion coefficient of a molecule in dense fluids at a given density and temperature plays an important role in many chemical processes. Molecular dynamics (MD) simulation has been recognized as a useful tool to provide exact results of theoretical models, thus affording a database for the development of empirical models that can be readily accessible for engineering purposes. The aim of this work is to provide self-diffusion coefficient data from MD simulation for freely jointed Lennard-Jones (LJ) chain fluids of lengths 2, 4, 8, and 16 at the reduced densities ranging from 0.1 to 0.9 and at the reduced temperature interval of 1.5-4. Based on both Chapman-Enskog formalism and MD simulation data, we propose an equation to calculate self-diffusion coefficients of polyatomic fluids. The new model represents the self-diffusion coefficients with an absolute average deviation (AAD) of 15.3%. (C) 2004 Elsevier B.V. All rights reserved.