Fewer than a hundred cases of paroxysmal dystonia have been described in patients with multiple sclerosis (MS). Even fewer cases of hemidyskinesia triggered by repetitive movements (paroxysmal kinesigenic hemidyskinesia--PKD) have been reported in MS patients. We describe the case of a woman, age 18 years at the onset of MS, and a man age 35 years at the onset of MS, who presented with PKD as the initial symptom. Magnetic resonance images (MRI) of these patients showed different areas of acute lesions possibly related to PKD; MRI of one of the patients demonstrated 1 lesion in the subcortical parietal area and another in the thalamic region and showed 2 lesions in the cervical spinal cord in the other patient.