The JCZ and BKW EOS are widely used to compute P-V-T relationships of the gaseous products of CJ detonations, but these computations need experimental verification. Quantitative comparisons of computed and experimental CJ parameters over a wide range of initial density&rgr;0are a good test of the validity of the above EOS. Particularly useful for such comparisons are two empirical linear functions:D=A+B&rgr;0and&rgr;CJ=a+b&rgr;0,and the adiabatic exponent&kgr;1for the CJ state. Reliable measured values of A and B exist for many explosives. Our previous publications obtained a, b, and&kgr;1based on experimental D’s and selected experimentalPCJ.Agreement among EOS computed and experimental values of A or B is unsatisfactory. This means that EOS-basedB&rgr;0/D,a critical factor in obtaining the CJ Gru¨neisen coefficient, Jones &agr;, and partial derivatives of many CJ variables can be in error. Computations ofaorbby variants of JCZ or BKW EOS differ from the empiricalaandb. Consequently, EOS-based&kgr;1’s,PCJ’s,and many CJ parameters that depend on&kgr;1may be in error. ©2000 American Institute of Physics.