Fostering services across the globe encounter difficulties in recruiting and retaining family foster- carers. Yet, we know little of the international and cross- cultural issues which impact on recruitment and retention. In this article, we draw on previous empirical research, and also on information collected during a recent study of global trends in family foster- care, to present an international comparative analysis of those issues. Three key themes emerged from the study: motivation and capacity to foster; professionalism versus altruism; and criteria for kinship and unrelated carers. Each of these presents a considerable challenge to foster- care services. Here, we explore these key themes further, and reflect on the implications for policy and practice.