The pyrene fluorescence measurements have been carried out for the micelle formation of sodium dodecyl sulfate (SDS), dodecyltrimethylammonium bromide (DTAB), and dimethylene bis(dodecyldimethylammonium bromide) (12-2-12) in the presence of fixed different amounts of various generations of poly(amidoamine) (PAMAM). The critical micelle concentration (cmc) of SDS decreases with an increase in the fixed amount of PAMAM, suggesting the facilitation of micellization due to the participation of SDS-PAMAM complex in the micelle formation. This behavior has not been observed for DTAB/12-2-12 in the presence of various generations of PAMAM. The results indicate that SIDS always has stronger interactions with all the generations of PAMAM in comparison to those of DTAB and 12-2-12. (c) 2004 Elsevier Inc. All rights reserved.