The micellization behavior of novel tertiary amine methacrylate-based ABA type triblock copolymers formed by poly[2-(dimethylamino)ethyl methacrylate] [PDMA] middle block and poly[2-(diethylamino)ethyl methacrylate] [PDEA] or poly[2-(diisopropylamino)ethyl methacrylate] [PDPA] side blocks, PDPA(m)-b-PDMA(n)-b-PDPA(l), and PDEA(m)-b-PDMA(n)-b-PDEA(l) was investigated. Both types of triblock copolymers were water-soluble and had potential for various applications due to their self-assembled and the bottom-up nanoscale micellar construction. The micellar aggregations of the triblock copolymers in aqueous solutions with varying comonomer ratios, molecular weights, temperatures, and pH values were investigated by small-angle X-ray scattering and dynamic light scattering. Compact micellar aggregations were obtained as 0.5 weight percent solutions at 20-21 degrees C and pH 8.67 to 9.05, and characterized as polydispersed spherical core-shells. One group of triblock copolymer micelles had PDPA-cores with radii from 18 to 21 angstrom and PDMA-shell thicknesses of 89-105 angstrom, whereas the other group had PDEA-core spherical micelles with core radii of 60-62 angstrom and a PDMA-shell thicknesses of 64-66 angstrom.