Micelle-mediated solute transport through nanoporous membranes can considerably increase total solute transport compared to free diffusion of solute alone. Micelle-mediated solute transport is of importance in chemical modification of porous media and controlled-release applications when the solute is sparingly soluble in water. Experimental and theoretical results are given for the transport of a local anesthetic, n-butyl-p-aminobenzoate, dissolved in a micellar solution of iso-octylphenoxypolyethoxyethanol through nanoporous polypropylene membranes. The membranes have slit-like pores with a characteristic dimension of 40 nm. The theory, based on the phase-separation model, is in good agreement with the experimental results on micelle-mediated transport of the anesthetic through the nanoporous membranes. Hindered diffusion of micelles inside the slit-like pores is taken into account in the theory since the micelles are spherical with a diameter of 9.28 nm.