The photochemically enhanced Fenton reaction producing hydroxyl radicals is used as the initiation step of the free-radical polymerization of 1-vinyl-2-pyrrolidone (VP) and copolymerization with methacrylic acid (MAA) at room temperature. The poly(N-vinyl-2-pyrrolidone) (PVP) homopolymer obtained by photo-Fenton method has a low molecular weight (Mw=54,000gmol−1) and polydispersity of about 3.1. The copolymerization of VP with MAA results in statistical copolymers with molecular weight in the range of (80–230)×103gmol−1 and polydispersity in between 2.4 and 1.7, when using a feed composition of MAA from 10 to 40wt.%. The copolymers have high percent of MAA relative to feed composition due to the higher reactivity ratio of MAA compared with VP. The photopolymerization rate is determined from dilatometry measurements, and its dependency with concentration of the Fenton reagent is established.