The behavior of charged spinning test particles moving along circular orbits in the equatorial plane of the Reissner–Nordström space–time is studied in the framework of the Dixon–Souriau model completed with standard choices of supplementary conditions. The gravitomagnetic "clock effect," i.e. the delay in the arrival times of two oppositely circulating particles as measured by a static observer, is derived and discussed in the cases in which the particles have equal/opposite charge and spin, the latter being directed along the z-axis.