The local wall shear stress, in turbulent flow of drag reducing and corrosion inhibiting surfactant solutions, was measured from polarographic mass transfer experiments using microelectrodes. A good agreement was observed between these values and those obtained by pressure drop measurements in a rectangular channel of high aspect ratio (10: 1). Irreversible degradation was not observed in these systems at variance with polymer solutions. (c) 2007 Elsevier B.V. All rights reserved.