Sertraline, a selective serotonin reuptake inhibitor (SSRI), was used in a dose of 25 mg orally daily in 12 moderate to severely depressed patients of end stage renal disease (ESRD) on maintenance haemodialysis. Virtually all of them showed features of hyperserotonin state and in 11 drug was stopped within 3 weeks. One of the patients developed almost fatal serotonin syndrome and required intensive care with ventilatory support. In our experience the use of SSRI, sertraline for depression in ESRD patients on maintenance haemodalysis was associated with a high incidence of serotonergic side-effects and toxic serotonin syndrome.