A case report and a review of the literature concerning electroconvulsive therapy (ECT) in the treatment of Parkinson's disease with special reference to the therapy of "on-off" phenomena is given. The first report of positive effect appeared in 1959 and, with a single exception, all published articles on this topic point to a positive outcome of ECT. There seems to be a specific anti-Parkinsonian effect alongside the well-known effect on various psychotic conditions. ECT thus must be considered a valuable intervention when drug therapy is insufficient, when prolonged medication leads to decreased efficacy, or when patients develop neuro-psychiatric manifestations. A short review of the pathophysiological mechanisms which may underly the effect of ECT in Parkinson's disease is given.