Background: Dementia imposes a heavy burden on health and social care systems as well as on family caregivers who provide a substantial portion of the care. Interventions that effectively support caregivers may prevent or delay patient institutionalization and hence be cost-effective. However, evidence about the cost-effectiveness of such interventions is scarce. The aim of this study was to evaluate the cost-effectiveness of a family meetings intervention for family caregivers of dementia patients in comparison with usual care over a period of 12 months. Methods: The economic evaluation was conducted from a societal perspective alongside a randomized trial of 192 primary caregivers with community-dwelling dementia patients. Outcome measures included the Quality Adjusted Life-Years (QALY) of caregivers and patients and the incidence of depression and anxiety disorders in caregivers. Missing cost and effect data were imputed using multiple imputations. Bootstrapping was used to estimate uncertainty around the cost-differences and the incremental cost-effectiveness ratio (ICER). The bootstrapped cost-effect pairs were plotted on a cost-effectiveness plane and used to estimate cost-effectiveness curves. Results: No significant differences in costs and effects between the groups were found. At 12 months, total costs per patient and primary caregiver dyad were substantial: €77,832 for the intervention group and €75,201 for the usual care group (adjusted mean difference per dyad €4,149, 95% CI -13,371 to 21,956, ICER 157,534). The main cost driver was informal care (66% of total costs), followed by patients' day treatment and costs of hospital and long-term care facility admissions (23%). Based on the cost-effectiveness acceptability curves, the maximum probability that the intervention was considered cost-effective in comparison with usual care reached 0.4 for the outcome QALY per patient-caregiver dyad and 0.6 for the caregivers' incidence of depression and/or anxiety disorders regardless of the willingness to pay. Conclusions: The annual costs of caring for a person with dementia were substantial with informal care being by far the largest contributor to the total societal costs. Based on this study, family meetings cannot be considered a cost-effective intervention strategy in comparison with usual care. Trial registration: ISRCTN register, ISRCTN90163486. © 2013 Joling et al.; licensee BioMed Central Ltd.