The entry and exit rate constants of naphthalene and pyrene to and from a micelle (k(+) and k(-), respectively) have been determined for n-decyltrimethylammonium trifluoroacetate (DeTAPA) and pentafluoropropionate (DeTAPP) micelles by a steady-state fluorescence quenching method. The k(-) values of naphthalene and pyrene for DeTAPA micelles increased with increasing temperature, whereas the values from DeTAPP micelles had a minimum at 308.2 K. The k(+) values of naphthalene and pyrene to DeTAPA micelles also increased with increasing temperature, whereas the values for DeTAPP micelles again showed a minimum at the same temperature. The fluorescence spectra of pyrene have indicated that the molecule is located at the hydrophilic outer site in DeTAPA and DeTAPP micelles rather than at the hydrophobic micellar core site.