There is a growing evidence base on the immediate and short-term effects of adult HIV on children. We provide an overview of this literature, highlighting the multiple risks and resultant negative consequences stemming from adult HIV infection on the children they care for on an individual and family basis. We trace these consequences from their origin in the health and wellbeing of adults on whom children depend, through multiple pathways to negative impacts for children. As effective treatment reduces vertical transmission, the needs of affected children will predominate. Pathways include exposure to HIV in utero, poor caregiver mental or physical health, the impact of illness, stigma, and increased poverty. We summarize the evidence of negative consequences, including those affecting health, cognitive development, education, child mental health, exposure to abuse, and adolescent risk behaviour, including sexual risk behaviour, which has obvious implications for HIV-prevention efforts. We also highlight the evidence of positive outcomes, despite adversity, considering the importance of recognizing and supporting the development of resilience. This study is the first in a series of three commissioned by President's Emergency Plan for AIDS Relief (PEPFAR)/United States Agency for International Development (USAID).