We synthesized five new Mannich bases compounds from vanillic acid and evaluated for their antioxidant activities using a free-radical DPPH and FRAP methods. The compounds' structures were confirmed based on infrared, proton NMR, carbon NMR, and mass spectra. In this study, the compound 5-(pyrrolidin-1-ylmethyl)vanillic acid (2e) showed the best free-radical scavenger activity, while compound 2-[(diethylamino)methyl]vanillic acid (2c) showed the best as a ferric reductant. Mannich bases enhanced the free-radical scavenger activity but decreasing the ferric reduction potential of the parent compounds. The compounds were found to be moderate antioxidant agents.