A Mexican judge has rejected an appeal by drugs lord Joaquin "El Chapo" Guzman against his extradition to the US.
The foreign ministry approved the extradition in May but Guzman's lawyers have been fighting the decision in a district court.
They say they will now take the case to a higher court.
The head of the Sinaloa Drug Cartel was recaptured in January after escaping for a second time from a maximum security prison.
Mexico has said it expects to extradite Guzman to the US by February. He faces multiple charges in the US, including drug trafficking and murder.
In a statement, the Mexican attorney general's office said the federal judge had "decided to reject the protection" sought by Guzman.
Andres Granados, one of Guzman's lawyers, said he would seek a Supreme Court hearing and might take the case to the Inter-American Commission on Human Rights.
"We are not defeated," he told AFP news agency.
Guzman is being held in a maximum security prison in Ciudad Juarez, near the US border. He was arrested in January after six months on the run following his escape through a tunnel in his jail cell.
He had already escaped a maximum security facility once before, spending 13 years at large.
Mexico agreed to transfer Guzman in May after the US guaranteed he would not face the death penalty.