The hydroxyl radical-scavenging activity of the amino-substituted α-tocopherol analogues was much higher than that of α-tocopherol. Aminochromanoxyl radicals generated from 5- and 7-aminochromanol were successfully detected in aqueous solution at room temperature during ESR measurements. The stability of the aminochromanoxyl radicals leads to a significant enhancement of the radical-scavenging activity.