In the international market of citrus some characteristics are required currently, like rind damage absence, good internal quality, an appropriate relation of soluble solids/ acidity and, mainly, a low number of seeds. Pollination is a natural process that controls the number of seeds in citrus fruit, which can be increased by cross-pollination between varieties. Thus, in countries that supply the international market, there is an ongoing research to study this influence. In Spain, Morocco, South Africa, and Australia, experiments have been developed to help citrus growers in planning their orchards, so they can produce fruits with high quality and low number of seeds. This research confirms the influence of cross-pollination on the number of seeds in citrus fruits.