The paper describes the studies on the thermo-oxidative decomposition behavior of two types of starch graft copolymers: starch-g-poly(citronellyl acrylate) copolymers with the grafting percent (%G): 21.3% ± 0.5, 35.8% ± 0.6 and 59.8% ± 0.3 and starch-g-poly(citronellyl methacrylate) copolymers with %G: 21.3% ± 0.4, 37.0% ± 0.2 and 51.8% ± 0.3 prepared applying the "grafting from" method. The decomposition course of copolymers by using the TG/DTG/DSC/FTIR analysis was evaluated. As it was found, the course of TG/DTG/DSC curves was independent on the %G but it was directly dependent on the type of analyzed copolymer. It resulted in completely different decomposition course of starch-g-poly(citronellyl acrylate) copolymers under the presence of oxidative conditions as compared to starch-g-poly(citronellyl methacrylate) copolymers. Thanks to applying the FTIR analysis of the gaseous products emitted under the heating of the studied materials, the detailed decomposition course of copolymers was evaluated.