A series of homopolymers of N,N-dimethylhydrazidomethacrylamide (DMHMAM) and copolymers with (N-isopropylmethacrylamide) (IPMAN) have been synthesized and investigated as kinetic hydrate inhibitors (KHIs) with a structure-II-forming synthetic hydrocarbon gas mixture in high-pressure steel rocking cells. The same polymerization method to give similar low molecular weights was used to aid KHI performance comparison. The homopolymer polyDMHMAM was found to give good KHI performance, significantly better than the related hornopolymer, poly(N,N-dimethylhydrazidoacrylamide) (polyDNIHAM), which does not have methyl groups in the backbone. This is in agreement with previous studies on N-alkylmethacrylamides. PolyDMHMAM also has no cloud point in deionized water up to 95+ degrees C, making it suitable for injection in high-temperature wells. A 1:1 N,N-dimethylhydrazidomethacrylamide/N-isopropylmethacrylamide copolymer (1:1 DMHMAM/IPMAM copolymer; M-n = 2100) also exhibited no cloud point in deionized water and showed an improved KHI performance over polyDMHMAM homopolymer (M-n = 2300) and poly(N-isopropylmethacrylamide) (M-n = 1300) of similar low molecular weights. Other ratios of monomers in DMHMAM/IPMAM copolymers did not show an improvement on the performance compared to the other copolymers. Protonation of polyDMHMAM to give only quaternary dimethylhydrazinium groups strongly lowers the KHI performance. High pH (8-9) also gave a worse performance than at pH 6.5, suggesting that partial protonation of polyDMHMAM is optimal for the best KHI performance.