The electrochemistry of pyridoxine (vitamin B6, VB6) was studied by cyclic voltammetry at a glassy carbon electrode. The electrochemical response of VB6 could be significantly enhanced by using 4-hydroxy-2,2,6,6-tetra- methylpiperidine-N-oxyl (HO-TEMPO) as a mediator via an electrocatalytic EC' mechanism with the oxoammo-nium ion of HO-TEMPO as the active oxidant. The catalytic rate constant was determined to be 5.4×103 (mol L-1)-1s-1 by using chronoamperometry.