We report isothermal-isobaric molecular dynamics simulation results for total and excess properties of 162 ternary mixtures of Lennard-Jones fluids. Simulations were performed at energy and size parameter ratios in the range (1 less than or equal to epsilon(CC)/epsilon(AA) less than or equal to 2; 1 less than or equal to sigma(CC)/sigma(AA) less than or equal to 2). In these mixtures, the component A consists of the smallest atoms, while the component C consists of the biggest atoms. The energy and size parameter ratios of the component B lie in the range (1 less than or equal to epsilon(BB)/epsilon(AA) less than or equal to 1.75; 1 less than or equal to sigma(BB)/sigma(AA) less than or equal to 1.75). Results are reported for mixture density, residual internal energy, excess enthalpy and excess volume of 120 equimolar mixtures and 42 nonequimolar mixtures at 5 different thermodynamic conditions : (kT/epsilon(AA) = 1, P sigma(AA)(3)/epsilon(AA) = 0.5); (kT/epsilon(AA) = 1.5, P sigma(AA)(3)/epsilon(AA) = 1.5); (k(T)/epsilon(AA) = 2, P sigma(AA)(3)/epsilon(AA) = 1 2); (kT/epsilon(AA) = 2, P sigma(AA)(3)/epsilon(AA) = 2.5) and (kT/epsilon(AA) = 3, P sigma(AA)(3)/epsilon(AA) = 2.5). Some of these simulation results are used to test the accuracy of the recently developed statistical mechanical perturbation theory and van der Waals one-fluid theory of ternary mixtures. Perturbation theory is very successful in describing simulation results of highly nonideal mixtures, while van der Waals one-fluid theory can describe moderately nonideal mixtures only.