OBJECTIVES: To determine whether counseling and support reduce the burden and depressive symptoms of spouse caregivers of patients with Alzheimer's disease (AD) during the transition to institutionalization. DESIGN: A randomized, controlled trial of an enhanced counseling and support program for spouse caregivers of persons with AD. Structured interviews were conducted with spouse caregivers at baseline, every 4 months during Year 1, and every 6 months thereafter for up to 16 years. SETTING: Outpatient research clinic in the New York City metropolitan area. PARTICIPANTS: Referred volunteer sample of 406 spouse caregivers of community-dwelling patients with AD enrolled over a 9.5-year period. INTERVENTION: Enhanced counseling and support consisting of six sessions of individual and family counseling, support group participation, and continuous availability of ad hoc telephone counseling. MEASUREMENTS: Outcome measures included burden (modified Zarit Burden Interview) and depressive symptoms (Geriatric Depression Scale). RESULTS: Burden and depressive symptoms were significantly lower for caregivers in the treatment group than for controls receiving usual care at the time of and after institutionalization. Nursing home admission itself significantly reduced burden and depressive symptoms in the intervention and control groups. CONCLUSION: Institutionalization alone can reduce caregiver burden and depressive symptoms, but enhanced counseling provides additional long-term benefits. The results offer some of the first clinical evidence of the benefits of enhanced counseling during the transition to institutionalization for caregivers of people with AD.