Single fibre electromyography was used to analyse responses of the pelvic floor muscles to electrical stimulation such as applied for the treatment of urinary incontinence. Using latency variation of consecutive responses of single motoneurons as a criterion, responses of the following types have been identified in the pelvic floor muscles: direct responses due to stimulation of the motor axons, oligosynaptic reflex responses, polysynaptic reflex responses conducted through different numbers of interneurons, and recurrent responses of antidromically activated motoneurons. It has been shown that the largest proportion of the obtained motor effect is due to the polysynaptic reflex responses. This implies several important advantages as compared to direct stimulation of motor axons, e.g. the physiological recruitment order of the motor units, and coordination and plasticity of the response. Therefore, electrical stimulation seems promising in cases of upper motoneuron lesion in which the spinal reflex arcs remain preserved.