Anionic polymerization of N,N-dimethylacrylamide (DMAAm) was examined in toluene with tert-butyllithium (t-BuLi)/bis(2,6-di-tert-butylphenoxy)ethylaluminum [EtA1(ODBP)(2)]. In the presence of excess amounts of the aluminum compound over t-BuLi, the polymerization proceeded in a living manner. Sequential block copolymerization of DMAAm and methyl methacrylate (MMA) with the same initiator underwent smoothly in both directions, that is, polymerization of MMA by poly(DMAAm) living anions and vice versa. Moreover, the copolymerization of an equimolar mixture of DMAAm and MMA proceeded in a monomer-selective manner to give a block-like copolymer; DMAAm was polymerized first followed by MMA polymerization through selective activation of DMAAm by the coordination of EtA1(ODBP)(2).