Activities of graphite supported and polycrystalline Pt in electrocatalytic oxidation of ethylene glycol in neutral unbuffered Na2SO4 solutions have been compared. Morphology and microstructure of supported Pt electrodes have been studied using scanning electron microscopy, high-resolution transmission electron microscopy and X-ray diffraction. Specific activity of Pt electrodes and sensitivity to poisoning has been found to depend strongly on their microstructure. Supported electrodes appear to be from four to six times less active than polycrystalline PI in the potential region between 0.3 and 0.9 V vs. SHE but much more stable to self-poisoning. The electrode microstructure has much less effect on the activity at high (over 0.9 V vs. SHE) anodic potentials.