The new deal lets American forces stay at Manas airbase
Kyrgyz President Kurmanbek Bakiyev has signed into law a deal allowing the US to continue using an airbase to support international forces in Afghanistan.
The deal was reached last month after the US agreed to more than triple the annual rent it pays for the Manas base to $60m (£37m).
Kyrgyzstan had announced in February it was closing the base.
It denied at the time that the planned closure was linked to a promise of $2bn (£1.2bn) in aid from Russia.
The base, near the Kyrgyz capital, Bishkek, has been used to transport troops to Afghanistan and refuel military planes.
The closure of the Manas facility, the only US base in Central Asia, would have come as a major blow to American operations in Afghanistan.
Kyrgyzstan allowed US forces to use the base in late 2001 when the Taliban were overthrown in Afghanistan.
The presence of a US base deep in a country that borders China and used to be part of the Soviet Union has been of concern to Beijing and Moscow, which also operates an airbase in Kyrgyzstan.
On Monday, Russia agreed to allow the US to fly troops and weapons across its territory to Afghanistan.
Correspondents say the new arrangement takes pressure off American supply lines through Pakistan, which have been under increasing attack by militants.