Chinese H425 helicopters for its army, at a ceremony attended by Bolivian ministers and Beijing's ambassador, local media reported.
Foreign minister Carlos Romero and planning minister Viviana Caro signed the accord with China's diplomatic representative in La Paz, Shen Zhiliang, in the presence of army chiefs.
"We believe these helicopters are crucial for the diverse needs of our military," said army chief Antonio Cueto.
The 12-seater aircraft will be delivered in 2012 and will also be used for civil defense, officials said.
Bolivia ordered six K-8 fighter aircraft from China in January to help its fight against drug traffickers as part of cooperation accord between the two countries.