Self-injurious behaviors (SIBs) in autism spectrum disorder (ASD) are destructive symptoms that can lead to dangerous injuries and life-threatening risks. Agitation and SIBs may not respond to psychopharmacological and behavioral interventions. There are reports in the literature on improvement after electroconvulsive therapy (ECT) in cases not responding pharmacotherapy. However, data on the efficacy of the therapy on the benefiting patients, the course of the treatment and on the use of maintenance ECT (m-ECT) are very limited. This report presents the clinical features and the course of m-ECT on two cases under follow up for pharmacotherapy resistant ASD with significant agitation, mood disorder and SIBs that could cause severe head traumas. The initial stage of therapy consisted of 7 sessions of ECT patients showed improvement after the 5th session. m-ECT were started since the agitation repeated one week after discharge despite ongoing pharmacotherapy. In the first case, m-ECT was continued once every two weeks for a total of 46 sessions; and in the second case a total of 18 weekly sessions were conducted. No significant side effects or complications were observed and the general state of well-being was preserved. Our paper is among the few that reported succesful treatment of agitation with m-ECT. m-ECT should be considered in treatment resistant cases.