More than six million children under the age of five needlessly die around the world each year, according to experts.
Vaccines and antibiotics could prevent millions of deaths
They are killed by diseases that can either be prevented or treated. These include Aids, diarrhoea, malaria, measles, and pneumonia.
Overall, 10 million children die every year before they are five years-old. Most deaths occur in just six countries - China, Democratic Republic of Congo, Ethiopia, India, Nigeria and Pakistan.
In a series of articles in The Lancet, experts say extra money and better public health policies could prevent two out of three child deaths.
The figures reveal that more than four million children die before they are one month old, largely because of problems at birth.
Diarrhoea: kills over 2m
Pneumonia: kills over 2m
Malaria: kills about 1m
Aids: kills about 0.3m
Measles: kills 0.1m
Another four million children die from diarrhoea or pneumonia. Malaria is responsible for one million deaths while HIV claims 300,000 lives each year. At least 100,000 children die from measles.
Four million deaths occur in sub-Saharan Africa alone while another 2.4m occur in India.
Sierra Leone has the highest child mortality rate in the world, with 316 out of every 1,000 children dying before they are five.
Researchers said a series of simple measures could prevent most of these deaths.
They suggested that encouraging new mothers to breastfeed their children could save 1.3m lives each year.
Highest child death rates
1. Sierra Leone
Breast milk can protect infants against diarrhoea and pneumonia by boosting their immune system.
Encouraging mothers to start giving their children food as well as breast milk at six months could save another 600,000 lives.
Researchers said this could help children to fight diarrhoea, pneumonia, measles and malaria.
A further 326,000 deaths from diarrhoea could be prevented if everyone had access to clean water and better sanitation.
The researchers said spraying insecticides could help to save another 700,000 lives by protecting against mosquitoes, which are responsible for spreading malaria.
Vaccinating against measles and haemophilus influenza type B (Hib) could save more than half a million lives.
Providing children with antibiotics to fight pneumonia, malaria, dysentery and blood infections would save an additional two million lives, while giving oral rehydration therapies to children with diarrhoea would save 1.5m lives.
There can be no further excuses for letting children die
World Health Organization
The United Nations has set a goal to cut child deaths by two-thirds between 1990 and 2015.
Dr Gareth Jones of UNICEF acknowledged that this target will be missed unless urgent steps are taken to improve child health.
Writing in The Lancet, he said: "We have just passed the halfway mark in this period and, unless there is substantial change very soon, the target will be out of reach."
Dr Jones said millions of lives could be saved by using existing drugs and vaccines.
"There is no need to wait for new vaccines, new drugs or new technology," he said.
"The main challenge today is to transfer what we already know into action, deliver the interventions we have in hand to the children, mothers and families who need them."
Jennifer Bryce of the World Health Organization said the international community needed to tackle the problem.
"There can be no further excuses for letting children die," she said.
"We need strong, coordinated leadership from governments, from the United Nations, development agencies and scientists."