BACKGROUND: Trazodone has been used widely to treat insomnia in depressed patients. When used in combination with electroconvulsive therapy (ECT), trazodone has been suspected to cause cardiovascular side effects. METHOD: A retrospective study was done of 100 patients who received ECT with concurrent trazodone. One patient was excluded because permission to review the patient's records had not been given. The remaining 99 patients were matched with control ECT patients. RESULTS: No statistically significant between-group differences were identified in cardiovascular side effects, although a trend toward more orthostatic hypotension was observed in patients taking trazodone. CONCLUSION: Administering low-dose trazodone for insomnia in conjunction with ECT does not appear to increase cardiovascular complications. The true incidence of adverse cardiac events was not higher than 3.66% at a 95% confidence level.