The electrical conductivity of thermoplastic elastomers (TPEs) modified with gaseous chlorine was studied. A TPE based on polyether (‘Vitur’-grade polyurethane) and the same TPE but with phosphorus-containing fireproofing agent were held in gaseous fluorine for 1 and 3 h, and were also treated with alcohol after fluorination. The surface morphology of specimens was studied using an atomic force microscope (AFM). The changes in morphology were similar to the changes observed after the surface fluorination of rubbers. The volume and surface resistivities were measured using an Agilent 4339B instrument (USA). In all cases, the volume resistivities of modified TPEs were two orders of magnitude lower than those of the initial TPEs. The introduction of a fireproofing agent leads to a 2.5-fold reduction in volume resistivity, and a 100-fold reduction in surface reactivity. The influence of the fireproofing agent is associated with it having an effect similar to that of fillers, and with the formation of a thin layer on the surface of specimens. it was shown that ethanol treatment leads to a reduction in volume resistivity.