The UN document, titled State of Food Insecurity in the World 2003 and compiled by the Food and Agriculture Organisation, (FAO) calls on the international community to address the "setback in the war against hunger".
Having reduced the number of hungry in developing countries by 37 million during the first half of the 1990s, the numbers increased again by 18 million in the second half of the decade, the report said.
FAO director general Jacques Diouf likened the 798 million people who constitute the poor in developing countries to a
"starving continent" bigger than Latin America "which goes unnoticed unless the world's compassion is momentarily captured by war or natural disaster."
Diouf went on to say that there was enough food to eradaicate hunger. "The problem is not so much the lack of food but the absence of a real political will."
The FAO report puts the number of global hungry at 842 million people, citing the most recent available figures, from 1999-2001. It said 10 million were in industrialised countries, 34 million in countries in transition and 798 million in developing countries.
The report focuses on the importance of agriculture and agricultural trade in developing countries as a means of eradicating hunger.
"International trade can have a major impact on reducing hunger and poverty in developing countries. Overall, countries that are involved in trade tend to enjoy higher rates of economic growth," said Diouf.
The UN food agency highlighted progress in Latin America the Caribbean, and China, among 19 countries which succeeded in reducing the number of hungry throughout the 1990s.