The anodic behaviour and corrosion of tin in various concentrations of isobutyric acid solutions has been studied by using cyclic voltammetry technique under different experimental conditions. The data reveal that the polarization curves are strongly pH dependent. It is clear that in the pH range from 2.4 to 4 no anodic peak appears. In the pH range from 5 to 6 only one anodic peak appears and the anodic peak current density (I-PA) in case pH 5 is greater than that in case pH 6. The anodic excursion spans of tin in isobutyric acid solution (pH 5) are characterized by the occurrence of a well-defined anodic peak (peak A), followed by a passive region. The passivation may be related to the formation and precipitation of oxide film on the electrode surface. The data reveal that increasing isobutyric acid concentration, temperature, and scan rate enhances the anodic peak current density (I-PA) and shifts its peak potential towards more positive values. Addition of some polyethylene glycols to the isobutyric acid solution (pH 5) decreases the current density of the anodic peak and shifts its peak potential towards the negative direction. These changes depend on the concentration and molecular weight of the polyethylene glycol added. (c) 2005 Elsevier B.V. All rights reserved.