Diet has been identified as a risk factor for various cancers. The geographic distribution of cancer frequency within the European Economic Community shows how the Mediterranean area has the lowest incidence rates for most tumours associated with diet. The first studies on diet and cancer realized in this area are fairly recent and their results have been especially informative. This article endeavours to review Spanish epidemiological studies on diet and cancer, highlighting the most important findings on colorectal, stomach, bladder and breast cancer and the repeated observations of the protective effect of high vegetable consumption of different tumours.