Consumption of pulses as components of healthy diets is encouraged because it is believed that this is likely to help in reducing the risk of common non-communicable diseases, including cancers. However, the evidence base for the role of pulses in prevention of cancers is unconvincing because of the difficulties, using conventional epidemiological tools, in ascertaining the quantitative contribution made by pulses to cancer risk. Advances in understanding of the biological basis of cancer and of the mechanisms of action of cancer-preventing compounds offer new insights into the role of food-derived substances and of diet—gene interactions in modulating cancer risk. Pulses contain a rich variety of compounds which, if consumed in sufficient quantities, may help to reduce tumour risk.