Great progress has been made in the development of social robots that can interact with us in entertaining and sometimes useful ways, and that appear to understand us. It has been suggested that robots could be placed in social roles such as those of children’s nannies, or teachers, or as carers and companions of older people. Before this happens, we must look at the available evidence and consider the likely effects. I will identify and discuss the ethical concerns that robots give rise to in different scenarios, as well as the potential benefits, focusing on those that involve the more vulnerable members of society. There is a pressing need to be aware of the risks of trusting robots too much and placing them in roles that they cannot adequately fulfil.