Electrochemical oxidation of arsenopyrite (FeAsS) has been investigated as an attempt to gain a better understanding of its dissolution chemistry. Rest potential measurements, cyclic voltammetry and constant potential experiments were conducted in the pH range from 8 to 12 in the absence and the in the presence of cyanide. A two-step reaction sequence is suggested by the electrochemical measurements. The initial step is described by: $$FeAsS + 6\,{H_2}O = Fe{\left( {OH} \right)_3} + {H_2}AsO_3^ - + S^\circ + 7\,{H^ + } + 6\,e$$ The second step involves the oxidation of the arsenite and sulfur according to the following reactions: $${H_2}AsO_3^{\rm{ - }} + {H_2}O = HAsO_4^{{\rm{2 - }}} + 3\,{H^ + } + 2\,e$$ and $$S^\circ + 4\,{H_2}O = SO_4^{{\rm{2 - }}} + 3\,{H^ + } + 6\,e$$ Stoichiometric determinations confirm that 14 electrons are involved in the overall reaction.