We have examined various flavors of HF+D(EFP) using two sizable data sets of noncovalent dimers. Overall, we find that the damping functions currently used for EFP dispersion are unsatisfactory from a formal standpoint as the power series in the modified Tang-Toennies damping function is truncated too early. Furthermore, replacement of an empirical damping parameter with a spherical Gaussian overlap integral fails to account for asymmetric Gaussian exponents on different centers. These errors lead to damping functions that do not satisfy correct limiting conditions. In particular, a generalized damping function that was introduced to extend the original formulation to odd powers of R (in order to incorporate R -7 dispersion) is divergent as R → 0 and thus does not serve as a damping function at all when the intermolecular separation is small. Ultimately, we recommend the parameter-free, BJstyle dispersion damping function introduced in Eq. ( ) as a replacement for the modified Tang-Toennies function that is presently employed in EFP. For the data sets examined here, the HF+D(EFP) method in conjunction with new damping function exhibits an accuracy that rivals existing EFP damping functions, yet the new approach is based on a correct theoretical framework and is extensible to odd powers of R. Given the extensive use of EFP across myriad computational chemistry applications, we expect that following this recommendation will minimize errors in many future studies by putting EFP dispersion on a more rigorous footing.