The January contract for West Texas Intermediate crude sank USD 2.32 to USD 37.65 a barrel on the New York Mercantile Exchange, a drop of 5.8 per cent.
In late-afternoon trade in London today, Brent North Sea crude also was languishing near 2009 lows.
The Organisation of the Petroleum Exporting Countries - which pumps about 40 per cent of the world's crude oil - decided on Friday against cutting output to raise prices.
"The decision by OPEC members to keep oil production output at record high levels has seen oil prices plummet again," said Sanjiv Shah, chief investment officer of Sun Global Investments.
He added that the decision "suggested that the organisation was effectively abandoning its long-term strategy of limiting production and acting as a cartel, leading to more downward pressures on oil prices in the short term".
OPEC countries are currently producing an estimated 32 million barrels per day, above the group's prior 30 million barrel target.
With Iran expected to resume substantial exports next year, hopes were high that the cartel would lower supplies.
But it has now put off a production reassessment to its next meeting on June 2, 2016, and gave no official output figures following Friday's latest meet.
"Crude oil prices were no doubt compressed by the lack of an agreement at the OPEC, signaling that the supply glut will persist longer," said analyst Bernard Aw at IG Markets in Singapore.
EY analyst Sanjeev Gupta added that market attention had now turned to an upcoming meeting of Fed policymakers and to the latest economic data from China, the world's top energy consumer.
Markets are watching whether the Fed will raise interest rates on December 16.
