A self-consistent theory of chain molecular liquids from polymer Kirkwood integral equations is presented. The theory predicts the intramolecular chain distributions and the intermolecular pair correlation functions from which thermodynamic functions can be correctly predicted. The utility of the theory is demonstrated with the chain distributions from self-consistent equations at zero density for swollen and collapsed states of the chains and numerical results for the structure and equation of state of athermal chain molecular liquids at various chain lengths and densities. Structural and thermodynamic predictions of the theory are compared with Monte Carlo simulation results. The theory agrees satisfactorily with simulation data for monomer packing fractions up to 0.25. The investigation of the chain length dependence shows that a plateau value is reached for the equation of state as the number of monomer units reaches a value between 20 and 50.