The effect of the additive non ionic polyacrylamide (PAM), was studied at the laboratory level, as refining crystalline grain in the copper electrorefining. Experiments were performed 24 h of electrolysis, using an electrolyte of copper sulphate acid, with 0.5 to 10 mgl(-1) polyacrylamide at 55 degrees C and a current density of 260 Am-2. The effectiveness of these organic additives in copper electrorefining was determined by directly measuring the surface roughness of the copper deposit and contrasted with the results of other instrumental techniques (SEM and metallographic analysis). The results of the analysis SEM, metallographic analysis and measurement of the surface roughness of the copper deposit, show that to concentrations as low as 0.5 mgl(-1) of this additive is manifested its property of tuner of grain. However, in the range of 7 to 10 mgl(-1) of polyacrylamide, it reaches an optimum size of grain for the deposit of copper in the cathodes.