The landmark ruling for environment management costs was in the suit that dates back to 1993 against Texaco, a firm later acquired by Chevron. The Ecuadorans allege that Texaco dumped billions of gallons of toxic waste into the Amazon rainforest.
The top regional court in Sucumbios province, in northeastern Ecuador, fully upheld the February 14, 2011 ruling against Chevron of $8.6 billion with an additional 10 per cent for environment management costs, a judicial source told AFP, speaking on condition of anonymity.
The original ruling also ordered Chevron "to publicly apologize to the victims" or pay twice the stated amount. Chevron has not apologized.
"I must state my satisfaction" over the ruling, President Rafael Correa told reporters in the southwestern city of Guayaquil.
"I believe justice has been done -- the damage that Chevron did in the Amazon basin region is undeniable," Correa said.
In a statement, Chevron lashed out at the ruling.
The decision "is another glaring example of the politicization and corruption of Ecuador's judiciary that has plagued this fraudulent case from the start," Chevron said, claiming that the judgment was "illegitimate" and "procured through a corrupt and fraudulent scheme."
Chevron "does not believe that the Ecuador ruling is enforceable in any court that observes the rule of law. The company will continue to seek to hold accountable the perpetrators of this fraud."
The firm said it was also pursuing efforts at an international tribunal and in the US courts to prevent enforcement of the ruling.
The lawsuit on behalf of Ecuadoran Amazon communities was originally filed in New York in 1993.
Separately, some of the original plaintiffs are also appealing, claiming that the amount Chevron was ordered to pay was insufficient.
Chevron, the second-largest energy company in the United States, has long claimed the Ecuadoran legal process was tainted.