Nonpolar block copolymers may be selectively multisite substituted in only one block with various functional groups, like carboxyl, hydroxy, or alkyl groups. In this way, block copolymers with unusual structures are easily accessible. The degree of substitution in the functionalized blocks may be controlled in a wide range and copolymers with various concentrations of substituents arise. The procedure of functionalization involves selective multisite metalation of the block copolymer by Superbase, made from 3-(lithiomethyl)heptane and potassium tert-pentoxide, and subsequent reaction of the metalated copolymer with an electrophile. Hydrophilic-hydrophobic block copolymers prepared by this method were investigated with regard to formation of micellar solutions in aqueous media.