¡¡¡¡Single walled carbon nanotubes (SWCNT) and room temperature ionic liquid (RTIL) were used to make a gel microelectrode for studies of the oxidation of nitric oxide (NO). The Faraday response of the gel microelectrode was contributed from two components: an outside-surface microdisk and a thin-layer cell formed by inner porous electrode materials, and enhanced by the thin-layer effect. An EC mechanism, electrochemical NO oxidation followed by a chemical oxidation, was proposed. The gel microelectrode with a Nafion? coating eliminated interferences from nitrite and some biomolecules, improved stability, and had a linear response range from 100 nM to 100 ¦ÌM.