Lack of nutrition, clean water and basic health services are still claiming the lives of young children - but the death toll is half of that in the year 2000.
Six million children worldwide died last year from preventable diseases and other complications - about half the number of similar deaths in 2000 when nations endorsed goals to end extreme poverty, the United Nations said today.
World leaders adopted the UN's Millennium Development Goals in 2000, a year in which 11.2 million children below age 15 died from preventable diseases, a lack of clean water, malnutrition and during birth.
That number fell to 6.3 million in 2017 - or one child dying every five seconds - according to the UN children's agency UNICEF, which published today's report along with other agencies and the World Bank.
"Millions of babies and children should not still be dying every year from lack of access to water, sanitation, proper nutrition or basic health services," said Princess Simelela of the World Health Organization.
Most deaths last year - 5.4 million - were children below the age of five, according to the report. Newborns account for around half of the deaths.
For children everywhere, the most precarious time is the first month of life.
In 2017, 2.5 million newborns died in their first month, and a baby born in sub-Saharan Africa or in Southern Asia was nine times more likely to die in the first month than one born in a high-income country.
That number has fallen "dramatically" since 1990, when 12.6 million children under five died globally from preventable causes, according to the report.
"We have made remarkable progress to save children since 1990 - but millions are still dying because of who they are and where they are born," said Laurence Chandy, director of data and research for UNICEF.
"With simple solutions like medicines, clean water, electricity and vaccines, we can change that reality for every child," he said in a statement.
But Chandy said that, without urgent action, 56 million children under five - half of them newborns - will die between now and 2030.
The UN in 2015 replaced the Millennium Development Goals with 17 Sustainable Development Goals, which set a deadline of 2030 to end poverty, inequality and other global crises, while promoting initiatives such as sustainable energy.
However, the UN said last year that progress has so far been too slow to meet the targets, mainly due to violence including war.
The sweeping 15-year agenda approved by the 193 UN member states tackles such issues including child mortality, climate change, education, hunger and land degradation.
Theirworld’s work on early childhood development is supported by the Conrad N. Hilton Foundation.