Vitamins are organic substances essential to the maintenance of many physiological functions, and necessary for growth. They are subdivided into two groups: the fat soluble vitamins which include vitamins A, D, E and K and the water-soluble vitamins which include Group B vitamins and vitamin C. The recommendations for vitamins intake must be evaluated at regular intervals, and vary according to the different methods used and the different environments assessed. The shortcomings, but equally the measures of prevention must be taken into account. In industrialized countries, provided that the diet is balanced and in the absence of chronic disease, the majority of needs are covered. Vitamin requirements vary depending on age, sex, state of pregnancy, chronic disease or a specific diet. In industrialized countries, chronic alcoholics and malabsorption cases represent groups at risk of vitamin deficiency. Dietary anamnesis remains the best tool to assess needs and nutritional deficiencies. In infants fed exclusively on milk, the required intake is easy to deduce; on the other hand, the needs assessment becomes more difficult with dietary diversification. In industrialized countries, vitamin D should be administered throughout one's life, and vitamin K during the first three months of life for breast-fed new-borns. In developing countries, nutritional status is precarious and supplementation needs to be adapted accordingly.