OPEC has agreed to cut oil supplies to world markets by 1.5 million barrels a day after a two-hour meeting in Vienna.
Kuwaiti Oil Minister Sheikh Saud Nasser al-Sabah said the decision was unanimous.
The pact reduces exports from 10 producer countries by just over 5% to 25.2 million barrels daily and is effective from February.
OPEC wants to defend the value of its crude near $25 a barrel. Prices had fallen from a ten-year high of $35 in October.
Oil ministers decided to curtail production despite concerns among major importing nations over the potential impact on energy costs and economic growth.
The US and the EU had urged the group to make only a modest reduction.
