BACKGROUND: Electroconvulsive therapy (ECT), though reliable and effective, is controversial due to its media portrayal as a treatment with severe side effects. Electroconvulsive therapy is mainly given to patients suffering from affective disorders and treatment-resistant schizophrenia. Although past research assessed the amount and duration of memory loss due to ECT, little is known about its influence on cognition for patients suffering from schizophrenia, whose cognitive decline is an inherent part of their illness. We aimed to test whether maintenance ECT causes cognitive decline among elderly schizophrenia patients. METHODS: Twenty elderly (age >65 years) patients suffering from schizophrenia and schizoaffective disorder who received maintenance ECT were matched with 20 controls suffering from the same illnesses that have never been treated with ECT. The match was based on age, sex, and illness duration. The participants were evaluated using the Montreal Cognitive Assessment for cognitive decline and a Positive and Negative Syndrome Scale (PANSS) for illness severity. RESULTS: A lower score in the abstraction subscale was found in the maintenance ECT population (P = 0.002), without significant differences in the total Montreal Cognitive Assessment and the delayed-recall subscale scores. In the treatment group, a correlation was found between an impairment in naming and positive symptoms in the PANSS score (r = -0.45) and between abstraction impairment and negative symptoms (r = -0.56) and total PANSS score (r = -0.497). CONCLUSIONS: Maintenance ECT does not worsen existing global cognitive deficits or delayed recall in elderly schizophrenia patients. The abstraction impairment was possibly due to the higher disease burden of the patients referred to ECT.