Cuba is the top-ranking developing country when it comes to protecting children's rights, according to a new Child Development Index (CDI).
This ranking reflects Cuba's progress since the 1990s in child health, nutrition and education, despite considerable difficulties,
Save the Children UK, an independent children's rights organisation, says it is "outraged that millions of children are still denied proper healthcare, food, education and protection".
It has developed the CDI as part of its strategy to "hold governments to account for children's wellbeing".
The index is constructed from three indicators: health (a scaled probability of death under the age of five), nutrition (the percentage of under fives who are moderately or severely underweight) and education (the percentage of primary-school aged children who are not enrolled in school).
A low score indicates low child deprivation.
Cuba's progress in recent years raised it from second place in Latin America (after Argentina) in the 1990s to first place in the period 2000-06.
Latin America was also the region with greatest improvement in recent years, mostly from reductions in child mortality and increased school enrolments. East Asia was the second most improved region.
Costa Rica and Argentina were second and third in both the Latin American and the developing country lists.
While wealthy OECD countries topped the list, the US, by contrast, went backwards. It now ranks 23rd in the world on children's rights — after Cuba, Costa Rica and Argentina.
The poor US performance was largely due to deterioration in primary school enrolments.
Save the Children UK observes that, worldwide, more than 9 million children under five die every year, one quarter of all children are underweight and 75 million primary school-aged children are not enrolled in school.
The group says that the basic rights of children all around the world "continue to be violated and denied' and proposes "dramatic action" to reverse the slowdown in progress on child malnutrition, efforts to convert economic growth into benefits for children and "a significant effort" to promote girls' education.