The present contribution reports on the synthesis and controlled polymerization of a novel acrylamide monomer containing phosphonated moieties, namely diethyl-2-(acrylamido)ethylphosphonate. This monomer appears to be of great interest due to the phosphonated moieties, which can lead to a wide range of applications, associated with the chemical stability of the acrylamide compared to more common (meth)acrylate monomers. Reversible Addition-Fragmentation Transfer (RAFT) polymerization of this monomer was investigated using two different trithiocarbonate chain transfer agents, and it allowed the synthesis of poly(diethyl-2-(acrylamido)ethylphosphonate) with controlled molecular weight and low dispersity. Additionally, a diblock copolymer was successfully prepared by a similar RAFT procedure using thermosensitive poly(N-n-propylacrylamide) as a macro-chain transfer agent. A combination of both stimuli-responsive and phosphonated ester or phosphonic diacid (after hydrolysis) containing blocks appears valuable for drug delivery or water treatment, for instance.