More than two billion people are estimated to be deficient in essential vitamins and minerals, also called micronutrients. Preschool-aged children and pregnant women are particularly vulnerable, and have high prevalence of iron and vitamin A deficiencies. Micronutrient deficiencies increase the risk of diseases such as diarrhoea, malaria and measles, leading to adverse consequences in growth and cognitive development of children, reproductive performance and work productivity. In population groups living in riparian and coastal areas, fish is an integral part of the everyday carbohydrate-rich diet. Small fish, eaten whole, with head, organs and bones are particularly rich in calcium; some are also rich in vitamin A, iron and zinc, and these nutrients in fish are more effectively absorbed than those in plant-source foods. In addition, fish has an enhancing effect on the absorption of iron and zinc from the foods in a meal. Small fish are more frequently consumed by the poor, and are likely to be distributed more evenly among household members than large fish or other animal-source foods. Small fish species can be used as a cost effective, food-based strategy to enhance micronutrient intakes in vulnerable populations, such as malnourished children, pregnant and lactating women, and people living with HIV/AIDS.