In England and Wales the level of violence is lower than that of many other countries, including notably the major epidemic of violence in the United States of America. However, even in England and Wales, violent crimes are increasing steadily and unless this is treated as a major public health issue we may well go down the same road as the USA. This article reviews the evidence, much of which is from America, in the hope that it will stimulate the development of strategies to reduce the level of violence in our society. Many of the underlying factors are known, although research is still needed to disentangle the effects of each of the many variables. At present too little of such research is based in the UK. The Government's Chief Medical Officer has identified the health of adolescents as one of four new areas of particular importance requiring broader discussion in the coming year and comments that 'adolescence is a crucial period during which lifestyles, values and attitudes are established'. This paper identifies the main risk factors which tend to breed antisocial behaviour in adolescents in so far as they relate to violence.