The interaction between poly(sodium 2-(acrylamido)-2-methylpropanesulfonate) labeled with 1 mol % pyrene (PyPAMPS) and mixed micelles of hexaethylene glycol n-dodecyl monoether (C12E6) and n-hexadecyltrimethylammonium chloride (CTAC), in which N,N-dimethylaniline (DMA) was solubilized, was studied by steady-state and time-dependent fluorescence quenching by varying the mole fraction of CTAC (Y) in the mixed micelle. At Y < 0.05, fluorescence quenching is essentially dynamic, arising from collisional encounters of the pyrene Sites and DMA-carrying mixed micelles. Strong quenching begins to occur at Y congruent to 0.05, corresponding to the onset of polyelectrolyte-micelle interactions. In the region 0.05 < Y < 0.09, the quenching was shown to occur via transient complex formation between PyPAMPS and the mixed micelle. Changes in the vibrational structures of fluorescence spectra of pyrene in PyPAMPS indicate that pyrene groups are inserted in the hexa(oxyethylene) phase of the mixed micelle when the polymer-micelle complex is formed. The extent of quenching reaches a limiting value at Y > 0.11 in excess micelle solution, corresponding to the state in which all pyrene groups are micelle-bound.