Summary Although several reports suggest that intermediate to high doses of propranolol (80–160 and 200–600 mg/day) can effectively treat aggressive behavior in dementia, significant side effects can occur at these doses. To minimize these side effects, we treated and followed-up a series of 12 demented patients, whose caregivers sought medical help for their disruptive, aggressive behavior, with low-dose propranolol monotherapy (10–80 mg/day). Assessment measures obtained at baseline and during treatment by caregiver interview included ordinal ratings of aggression severity, the Cohen-Mansfield Agitation Inventory (CMAI), and the California Behavior Questionnaire (CBQ). The aggression ratings showed that low-dose propranolol effectively reduced aggression in eight of 12 patients (67%) within 2 weeks of treatment and remained effective for the duration of follow-up (1 to 14 months). Subscales of the CMAI showed responders to have significant reductions in physical and verbal aggression/agitation and in pacing/wandering. These results suggest that low-dose propranolol should be further studied for treating aggression or agitation in demented patients.