The number of under five year olds who die every year has dropped from 12 million in 1990, to 7.6 million in 2010, say UNICEF and the World Health Organisation.
Globally, that means about 12,000 fewer children under 5 die every day than did 21 years ago.
Better access to proper health care, immunisation, prevention and treatment of childhood diseases, clean water and better nutrition are what’s driven the improvement, the organisations said. Even Sub-Saharan Africa, which has one of the world’s biggest rates of child mortality lowered its rate by double.
The achievement meets the United Nations goal of cutting child mortality by 2015, although aid agencies say more money is needed.
"This is proof that investing in children's health is money well spent, and a sign that we need to accelerate that investment through the coming years," said the WHO’s Dr Margaret Chan.
Six of the 14 best-performing countries were in Sub-Saharan Africa, as are four of the five countries with the biggest overall reductions (more than 100 deaths per 1,000 live births). Malaria is still a major killer in the area, however, killing about 16 per cent of under-five year olds.
Yet more than 21,000 children still die every day from preventable causes, the report highlights. Babies run the largest risk of dying - more than 40 per cent of deaths in children under five happen in the first month of life and more than 70 per cent are in the first year of life.
The four major killers of under five year-olds worldwide are pneumonia, premature birth and complications in birth and malnutrition. Malnutrition is the underlying cause in more than a third of the deaths of under fives, the report said.
"Focusing greater investment on the most disadvantaged communities will help us save more children's lives, more quickly and more cost effectively," said UNICEF’s Anthony Lake.
Cutting child mortality even more will need more targeted investment in healthcare networks and services, especially in more hard-to-reach areas, UNICEF said. It also found a growing gap between children who have benefited from the fast economic development in the region, mostly in cities, and those on the fringes of society such as ethnic minorities, and children in the more cut-off country areas.