An　electrochemical　sensor　was　developed　for　the　detection　of　organophosphate　pesticides　based　on　electrodeposition　of　gold　nanoparticles　on　a　multi-walled　carbon　nanotubes　modified　glassy　carbon　electrode.　Cyclic　voltammetry　was　employed　in　the　process　of　electrodeposition.　Field　emission　scanning　electron　microscope　and　X-ray　diffraction　techniques　were　used　for　characterization　of　the　composite.　Organophosphate　pesticides　(e.g.　parathion)　were　determined　using　linear　scan　voltammetry.　A　highly　linear　response　to　parathion　in　the　concentration　range　from　6.0　x　10(-5)　to　5.0　x　10(-7)　M　was　observed,　with　a　detection　limit　of　1.0　x　10(-7)　M　estimated　at　a　signal-to-noise　ratio　of　3.　The　method　has　been　applied　to　the　analysis　of　parathion　in　real　samples.