Cancer is said to be due to nutrition in 35 cases out of 100, ranging from 10 to 70% by sites. Saturated fats show a positive relationship with cancer, while vitamins, vegetables and cereals show a negative relation with it. This work was aimed at studying the relationship between nutrition and cancer in different Italian areas. Cancer mortality rates collected in 94 National Health units over the period 1980-82 have been correlated with the average food consumption of individuals registered in the same units. All the nutrient groups have shown evidence of a correlation between nutrient intake and mortality rates. Fats, animal proteins and saturated fatty acids showed the strongest positive correlations; vegetable proteins, fibre, carbohydrates, oleic acid, vitamins C and B1 gave negative correlations. Thus, it can be concluded that (a) this ecological analysis has confirmed previous hypotheses concerning the role of vegetables in cancer prevention and (b) the relation between nutrition and cancer mortality could be even stronger if applied to the whole population, since a 1-g increase in vegetable protein consumption would result in a reduction of 2.5 cases out of 100, a 1-g increase in fibre would result in a reduction of four cases out of 100 and a 1-g increase in animal fat would result in an increase of one case out of 100.