Russia has agreed to lend Venezuela over $2bn to purchase tanks and advanced anti-aircraft missiles.
President Hugo Chavez said the purchases he had agreed would include 92 tanks and an S-300 missile system that can shoot down fighter jets and cruise missiles.
Two years ago, Russia agreed to sell the same missile system to Iran, but they were never delivered due to US and Israeli concerns that they would be used to defend Iran's nuclear installations.
Mr Chavez claims the US could attack Venezuela for its oil reserves.
He explained that Moscow was helping Venezuela develop nuclear energy, but that he has no intention of developing an atomic bomb.
Venezuela's finances have suffered this year due to lower crude prices.
President Chavez said he needed to borrow the money for defence to avoid cuts in education and health.
Venezuela is embroiled in a diplomatic dispute with Colombia over a deal to allow US troops into more bases in the neighbouring country to help fight drug traffickers and militants.
President Chavez, a fierce critic of US foreign policy, says the Colombian bases plan could be used to launch an attack on Venezuela and increases the risk of war in South America.
It was not immediately clear when Venezuela would receive the new weapons.
