Technical Abstract: Even though assessment of micronutrient status is a major concern in public health nutrition, there are serious limitations to the available indicators. These include cost, lack of congruence between cut-offs used to denote deficiency and adverse functional consequences, and inconsistent methods of dealing with the confounding effect of infections on micronutrient status indicators. Methods to assess the functional consequences of micronutrient deficiencies are even less well developed, and not focused on outcomes known to be sensitive to deficiencies. Notable breakthroughs in the development of indicators include ability to measure several indicators simultaneously in small samples of blood or serum dried on filter paper, the use of change in body stores of iron or vitamin A to assess bioavailability and efficacy or effectiveness of a micronutrient intervention, and calculation of the prevalence of micronutrient intakes below the Estimated Average Requirement. Further improvements in methods to assess micronutrient status are needed urgently.