The interactions between dendrimers and surfactants led to the formation of aggregates dispersed in aqueous solutions. The potential of the resulting dendrimer-surfactant aggregates as new drug formulations was evaluated. The size, morphology, and stability of the aggregates and the localization of drugs in them were determined by dynamic laser light scattering, atomic force microscopy, agarose gel electrophoresis, and nuclear magnetic resonance studies. The drug-loaded aggregates have a spherical shape and an average size of 40 nm. The drug-loading efficiency of dendrimers is significantly influenced in the presence of surfactants. The release rate of the drugs from the dendrimer-surfactant aggregates can be modulated by varying the amount of surfactant in the aggregates. The dendrimer-surfactant aggregates are promising carriers for hydrophobic drugs in transdermal administration routes.