Carbon powder modified with lead(IV) oxide was synthesised by a wet impregnation procedure from concentrated lead(II) nitrate solution. The impregnated powder was subsequently thermally treated at 823 K. Electrochemical and spectroscopic characterisation of the modified powder showed that lead(IV) oxide has been formed during the procedure. A novel composite lead(IV) oxide modified carbon powder epoxy electrode was developed for electrocatalytic sensing of gaseous, inorganic and organic analytes. The behaviour and analytical advantages of the composite electrode are evaluated with respect to determination of ammonia, nitrite ions and several different phenols. It has been demonstrated that the composite electrode can be used to analyze these analytes in standard aqueous solutions with competitively low limits of detection.