The paper presents an oxygen sensor based on ionic liquids and solid electrodes. The following ionic liquids have been employed: [BMIM][BF4], [HMIM][Cl], [BMIM][N(CN2)]. Minimum time of the sensor exposure to analyte, after which the signal (current intensity) was stable, has been evaluated. An impact of volumetric flow rate of analyte on the sensor exposure time and signal has been determined. A product of permeability coefficient and solubility of oxygen in ionic liquids has been estimated. A mechanism of oxygen reduction on a surface of the solid electrodes, in the ionic liquid environment has been presented. Overall cathodic coefficients of transition for the sensors with particular ionic liquids have been determined as a function of potential scan rate. (C) 2011 Elsevier Ltd. All rights reserved.