The increasing consumption of junk food and snacks in Chile in recent years and its association with marketing strategies and prevalent diseases, is reviewed. In the context of world economy, junk food is a global phenomenon. The availability of junk food and snacks at low prices and marketing has triggered an evolution of consumption of foods that require neither the structure nor the preparation of a formal meal. Many studies have suggested that the increase in snack consumption is associated with an increase in obesity, tooth decay and other chronic diseases among children and adolescents. The hypothesis suggests a link between the pattern of snack consumption and an increase in the energy density of food consumed, a decrease in satiety, passive over consumption, and an increase in obesity. Between 1977 and 1996, the contribution of snacks to daily energy intake among children between 2 and 5 years increased by 30% in the United States. In each age group in Chile, the frequency of non-transmissible chronic diseases is increasing due primarily to a westernized diet that is high in fat, cholesterol, sodium, and sugar and a sedentary lifestyle. Education about junk food consumption and healthy eating habits in the family, starting since childbirth and public policies about healthy lifestyles should be strengthened (Rev Méd Chile 2004; 132: 1235-42)