Bolivia has joined Brazil and the United States in signing an accord to cooperate in the control of coca plant cultivation.
Coca is used for traditional medicinal purposes in the Andean region but is also the raw material of cocaine.
Friday's signing had been delayed five times while Bolivia sought changes in the document's wording.
The agreement follows the restoration of Bolivia-U.S. ties in November. Bolivian President Evo Morales expelled the U.S. ambassador and DEA in 2008 for allegedly inciting the opposition.
The agreement creates a coca cultivation tracking system, with the U.S. providing GPS equipment and Brazil capturing satellite images. The U.N. Office on Drugs and Crime is also participating in the project.