Gold nanoparticles were deposited electrolessly on multiwalled carbon nanotubes ( CNTs ) via in situ reduction of HAuCl4 by NaBH4. The resulting gold covered nanotubes were immobilised onto the surface of a glassy carbon electrode via evaporation of a suspension in chloroform. Anodic stripping voltammetry was performed with the modified electrode in As(III) solutions. A limit of detection (LOD based on 3 was obtained but more importantly a sensitivity of 1985AM−1 was obtained with square wave voltammetry (SWV) in an optimised system with a deposition time of 120s. These values, particularly the high sensitivity compare favourably with previously reported methods in the area of electrochemical arsenic detection