According to the UN report, one of the contributing causes to more than one-third of child deaths worldwide is "under-nutrition".
Despite progress in reducing the number of underweight children, UNICEF reports there are an estimated 148 million children in the developing world who are undernourished, it added.
The report further said that about 9.2 million children under-five died last year around the world, compared to 12.7 million children deaths in 1990.
In the developing world, that accounts for 68 deaths per 1000 live births in 2007. And, on an average, there are just six deaths per every 1000 live births in industrialized countries.
But, improvements in child mortality have been made in all regions, including sub-Saharan Africa, where most of the fatalities occur, added the report.
According to the report, child mortality in Africa still remains high, and the worst rate in the world is in Sierra Leone where 262 out of every 1000 children die before they turn five.
Terming the results as "encouraging", UNICEF Executive Director Ann M. Veneman said that there have been improvements in early and exclusive breastfeeding, measles immunization, Vitamin A supplementation, the use of insecticide-treated bed nets to prevent the spread of malaria, and HIV/AIDS prevention and treatment - all credited for the improved numbers.
"These interventions are expected to result in further declines in child mortality over the coming years," cbs.com quoted her as saying.