This paper presents resistivity data for a range of surface‐grafted and copolymerized polymers and some challenges yet to be faced in resolving the effects of surface modification on their surface properties, in particular on electrical resistivity in their surface regions. The principal substrates used for measurement were polyaniline (PAN), low‐density polyethylene (LDPE) and polytetrafluorethylene (PTFE). Electrical resistivity has been determined as a function of graft monomer type (acrylic acid, sodium salt of styrene sulphonic acid and N,N‐dimethylacrylamide), graft temperature, grafting time and plasma pretreatment time. In the case of grafted PTFE, the effect of an emeraldine coating on resistivity is also determined. Copyright © 1999 John Wiley & Sons, Ltd.