A series of G(0) and G(1) generation 1,3,5-tris(3-aminopropyl)benzene dendrimers surface modified with the amino acids phenylalanine (Phe), methionine (Met), aspartic acid (Asp), and diaminopropionic acid (Dap) was investigated with regard to their stability against enzymatic hydrolysis with the model enzymes papain, chymotrypsin, trypsin, and pepsin. Additionally, the cytosol of MCF-7 cells was used to get an insight into the possible degradation in intracellular medium. The cytosol, chymotrypsin, and papain had similar activities on the tested dendrimers and efficiently cleaved methionine and phenylalanine from the surface of the dendrimers. The cellular uptake of the dendrimers into the MCF-7 cells depended on the surface modification (Phe>Met unmodified>>Dap=Asp) and the generations (G(0)>G(1)).