The Obama administration says the governments of Bolivia, Myanmar and Venezuela are the world's most derelict when it comes to fighting drugs.
The State Department's annual report on narcotics control criticizes Bolivia for failing to control coca growing or stem a significant rise in cocaine production.
It says Myanmar, a top heroin producer, often allows armed groups to traffic drugs if they cooperate with the government.
And Venezuela's "permissive and corrupt environment" has made it a major drug transit country. Narcotics flights, cargo containers, fishing vessels and "go-fast" boats move some 250 metric tons of cocaine out of the country each year.
The report called Venezuelan police corruption a major problem. It said the government hasn't punished officials linked to a Colombian terrorist group, the leftist Revolutionary Armed Forces of Colombia, or FARC.