The 40 substantive rights contained within the United Nations Convention on the Rightsof the Child (UNCRC) 1989, have applied, without discrimination, to all children in theUnited Kingdom since 1992. However, recurrent tragedies starkly highlight the potentialvulnerability of some children when their parents experience mental health difficulties;and many children affected by parental mental illness remain a hidden population, theunique challenges they face going unaddressed. Article 3 of the UNCRC states: ‘‘Allorganisations concerned with children should work towards what is best for each child’’.Social workers occupy a critical position in safeguarding the UN Convention rights ofchildren, particularly in situations where mental illness is having an adverse impact onparenting, and where children are ‘‘in need’’ or ‘‘at risk’’. However, collaboration betweenMental Health and Family & Child Care services can be problematic. Poorly-integratedservice provision constrained by inadequate resources and training, and complicated by alatent dichotomy between the human rights of parents and the Convention rights ofchildren, can contribute to regrettable outcomes for these most vulnerable families. Thisarticle highlights the potential psychological vulnerability of children living in a situationwhere one or both parents experience mental health difficulties. Evidence regarding thescale and impact of parental mental health difficulties is explored, and discussed in thecontext of the UNCRC, and the key findings of recent Child Protection Inspections andThe article draws on relevantliterature (specifically the Western and Eastern Health and Social Services BoardsInquiry into the tragic deaths of Madeleine and Lauren O’Neill in Northern Ireland, andthe preliminary findings of research being carried out by the authors within theUniversity of Ulster) to illustrate and consider the problems associated with effectivesocial work practice with these families. The article concludes by making recommenda-tions to enhance effective, responsive, collaborative social care provision for children infamilies experiencing parental mental health difficulties.