The role of informal carers in long-term care sheds light on the struggle related to population ageing and the increasing incidence of chronic disease. However, despite the increasing number of informal carers, most of them experienced the burden of caregiving. Since various policies have been implemented across countries to support informal carers, their attitude toward support services should be addressed. This research consisted of investigating how formal home care affected the utilisation of support services by informal carers. Data used stemmed from the 2015 Survey Capacité Aide et Ressources des Seniors ("CARE ménage") collected in France; and the National Health and Aging Trends Survey (NHATS) with the National Survey of Caregiving (NSOC) in the United States of America (U.S.). Andersen's health behavioural model of support services utilisation provided a conceptual framework for investigating predisposing, enabling, and need variables associated with informal carers services use. We used a probit model for econometrics modelling. We also checked for the endogeneity of formal care. A sample of N = 4,866 in France and N = 1,060 in the U.S. informal carers and care recipients' dyads were used in the study. In France, the care recipients' formal care utilisation does not influence the carer support service use. Comparatively, in the United States, formal care significantly increases the respite services utilisation by informal carers. This study provides important implications for Long-Term Care (TLC) dedicated to health policy, for an optimal trade-off between informal and formal care use, bearing in mind health system specificities. First, countries may spend more funds in innovative support programs in access to care, because some carers may have difficulties in accessing and using support services. Secondly, to provide and foster information campaigns to raise awareness concerning the utilisation of various existing health services, to improve social welfare..