To improve the efficacy and bioacceptability of polyamidoamine (PAMAM) in potential biomedical applications, the PAMAM dendrimers (first generation) were partially modified with cholic acid. (1)H NMR studies and acid-base titration show that two cholic acid molecules are linked to one PAMAM. The modified PAMAM dendrimers self-assemble to form dendritic multimolecular micelles in aqueous solutions, with a diameter of 120 nm measured by dynamic light scattering. These micelles can encapsulate hydrophobic drug molecules in aqueous media and exhibit pH sensitivity. The in vitro results demonstrate that the anticancer activity of camptothecin is significantly enhanced at low drug dose after being encapsulated by these micelles in the presence of serum. Therefore, the dendritic multimolecular micelles based on low generation dendrimers may have potential applications in the delivery of drugs.