Objective: To determine whether functional electrical stimulation-supported ergometric training of patients with multiple sclerosis has a prosthetic or therapeutic effect on biomechanical (power, smoothness of cycling) and functional outcomes (walking capability, strength of muscle, spasticity). Design: Twelve subjects with multiple sclerosis participated in an electrical stimulation-supported ergometric training (3 sessions/week for 2 weeks). Measurements were to study prosthetic (with and without stimulation) and therapeutic effects (before and after training). Methods: Power and smoothness were calculated, spasticity; strength and walking capability were measured by the Modified Ashworth Scale, Manual Muscle Test, and 10-Meter Walk Test. Results: The power and smoothness of pedaling significantly improved prosthetically with electrical stimulation, but did not show significant improvement over the 2 weeks of training. Significant short-term reductions of spasticity (before vs. after training session; p < 0.05) were found. Isometric strength did not increase significantly during the 2-week training period and there was no improvement in walking ability. Conclusion: Patients with multiple sclerosis are able to improve their cycling power and smoothness by pedaling with stimulation. Severely affected patients benefit more from FES-cycling therapy than slightly affected patients do.