An estimated $1tn (£600bn) a year is being taken out of poor countries and millions of lives are lost because of corruption, the BBC reported, citing campaigners.
Corrupt activities include the use of phantom firms and money laundering.
The report blames corruption for 3.6 million deaths every year.
If action were taken to end secrecy that allows corruption to thrive – and if the recovered revenues were invested in health – the group calculates that many deaths could be prevented in low-income countries.
One describes its findings as a “trillion dollar scandal.”
“Corruption inhibits private investment, reduces economic growth, increases the cost of doing business and can lead to political instability,” the report says.
“But in developing countries, corruption is a killer. When governments are deprived of their own resources to invest in health care, food security or essential infrastructure, it costs lives and the biggest toll is on children.”