Double hydrophilic statistical, diblock and triblock copolymers comprised of acrylamide and acrylic acid units have been synthesized in aqueous medium using the MADIX process. Starting from an either monofunctional or difunctional xanthate, the resulting AB and ABA-type double hydrophilic block copolymers (DHBC) exhibited molar masses predetermined by the initial monomer/xanthate precursor molar ratio and polydispersity indices in the range 1.2-1.5. Batch copolymerizations yielded well-defined statistical copolymers that were chain-extended for the synthesis of novel poly(acrylic acid-stat-acrylamide)-block-polyacrylamide DHBC.