A methodology is developed for molecular transport in nanopores, based on physical attributes requiring neither molecular dynamics simulations nor empi rical correlations. The proposed approach is reasonably rigorous yet easy to apply. The models extend the conventional theoretical framework(1-3) by eliminating key restrictive assumptions, such as uniform pore-size and hard-sphere molecules using several new mathematical treatments and the multisite potential equation,(4,5) making them more applicable to practical porous media. Importantly, one of the models reported using integral mean value theory develops an equation with the same format as a widely used formula with two empirical parameters, providing new, physical insights into the utility of this model. Literature data carbon tetrachloride and benzene transport in a commercial Ajax activated carbon are used as two case studies to demonstrate the applicability of the proposed methodology to practical systems, with good agreement between simulations and measurement data. (c) 2008 American Institute of Chemical Engineers.