Vitamin A deficiency in Central America was first identified as a public health problem in the 1950s. It affected primarily children. The main underlying cause was a deficient intake of pre-formed vitamin A, but infection and intestinal parasitism also played important roles. INCAP focused its efforts on overcoming this problem and developed, as a short-term solution, the technology to fortify sugar with vitamin A. Fortification programs were implemented in several Central American countries. Evaluation of these programs revealed a significant impact-not only on vitamin A status, but also on iron nutrition and hematological condition. Longer-term solutions, like increasing the availability and consumption of vitamin A-rich foods, were later suggested and operational tools were developed to assist the countries in the region in the implementation, evaluation and monitoring of their own fortification programs.