Agricultural and industrial residues obtained after isolating essential oil very often constitute more than 99% of the raw material and represent a potential natural source for antioxidants and other valuable substances; however, nowadays they are poorly exploited. For the first time, this study investigated antioxidant properties and bioactive compounds in the deodorized residue extracts of Myrrhis odorata leaves collected in Lithuania and South of France in order to evaluate the potential of by-products obtained after essential oil isolation as a source for antioxidants. The extracts isolated with polar solvents were strong antioxidants, mainly due to the presence of kaempferol-7-o-glucoside and cynarin, which were reported in Myrrhis odorata for the first time. Deodorized residues of mature leaves of Myrrhis odorata were valued as an antioxidants bioresource for the first time.