Background: spousal caregivers are usually of the same age as the dementia patient and therefore at risk of age-related cognitive decline. Suboptimal cognitive functioning in caregivers may have profound implications. Methods: fifty-four spousal caregivers of dementia patients from the Memory Clinic of the Academic Hospital Maastricht and the Regional Institute for Community Mental Health Care in the Netherlands were compared with 108 non-caregiving controls. Data were collected on patient and caregiver characteristics and caregiver cognitive functioning. Repeated measures statistical analyses were carried out to investigate the relationship between caregiver cognitive functioning at baseline and patient behavioural problems and caregiver competence during 1 year of follow-up. Results: caregivers performed significantly worse on several cognitive domains compared with control subjects. Low performance on a verbal memory task was related to a decrease in caregiver subjective competence and an increase in patient hyperactivity. Conclusion: the results indicate that screening for cognitive impairment of spousal caregivers may be helpful, because suboptimal cognitive functioning may affect the ability to provide adequate care.