Some 84% of children globally are in primary schools, Unicef says
The lives of children around the world have been "transformed" after the adoption 20 years ago of a UN treaty guaranteeing their rights, Unicef says.
In a special report, the UN children's agency says child mortality has fallen and more are now going to school.
But it says about 24,000 children die every day of preventable diseases and up to 1.5bn experience violence.
It adds that climate and population changes also threaten recent advances in child rights.
Unicef issued its State of the World's Children report on the eve of the 20th anniversary of the UN Convention on the Rights of the Child.
The report says that the document "has transformed the way children are viewed and treated throughout the world".
It highlights the following achievements:
- the number of under-fives dying each year has fallen from about 12.5m in 1990 to an estimated 8.8m in 2008
- some 84% of primary-school-age children are in class today and the gender gap is narrowing
- important steps have been taken to help protect children from serving as soldiers or trafficked into prostitution or domestic service.
But the report stresses that children's rights are still far from being assured.
"It is unacceptable that children are still dying from preventable causes, like pneumonia, malaria, measles and malnutrition," Unicef executive director Ann Veneman said.
She added that "millions lack protection against violence, abuse, exploitation, discrimination and neglect".
Ms Veneman stressed that "the big challenge of the next 20 years is to firmly position the best interests of children at the heart of all human activity".
The UN Convention on the Rights of the Child has been ratified by 193 countries - the widest support of any human rights treaty.
The US and Somalia are the only two nations yet to back the convention.