Crime may be regarded as a major source of social concern in the modern world. Very often increases in crime rates will be treated as headline news, and many people see the law and order issue as one of the most pressing in modern society. It may be argued that the existing approaches to managing crime prevention may not be good enough to deal with such events. In order to gain a full understanding and comprehensive awareness of crime risk in a given situation it is necessary to consider in a coherent way all the aspects that may produce it. In short there is a need for a systemic approach to public safety. Systemic means looking upon things as a system. A system may be defined as any entity, conceptual or physical, which consists of inter-dependent parts. To see things in a systemic way is to see events as the products of the working of a system. Given this, we may see crime as the product of a system and, within that, see assault/robbery/sexual offence etc., as results of the working of systems. A systemic approach to crime prevention in Mexico City is being pursued. This paper gives an account of the work.