The former first lady of the Philippines, who became renowned for her lavish collection of shoes, has been found guilty of seven counts of corruption during her twenty years in office.
Court officials said Marcos, who was not at Friday's hearing, would be able to avoid incarceration by posting an as yet undetermined bail.
Marcos, a sitting three-term congresswoman, has registered as a candidate next May to succeed her daughter, Imee Marcos, 62, as governor of Ilocos Norte, the stronghold of the still powerful Marcos family.
Marcos said in a statement her lawyer is "studying the decision and he has advised us that he intends to file a motion for reconsideration". The charges, the result of a court case which has been running for two decades, relate to private foundations she set up in Switzerland while holding public office between 1968 to 1986.
Sison said Imelda should be immediately arrested and return all stolen money from the Filipino people.
Marcos, who is now a member of the House of Representatives, is running for a governor post in next year's general election.
In the 21 years that President Ferdinand Marcos was in power, he and his wife became infamous for amassing billions of dollars, with funds funnelled into Swiss bank accounts.
Imelda Marcos was acquitted on Friday in three other cases, which were filed in 1991 and took almost three decades of trial by several judges and prosecutors.
Marcos can also raise the decision to the Supreme Court if she finds grave abuse of discretion on the part of the Sandiganbayan.
President Rodrigo Duterte, an ally of the Marcoses, said previous year the Marcos family had indicated a willingness to return a still-unspecified amount of money and "a few gold bars" to help ease budget deficits.
Akbayan Representative Tom Villarin said the guilty verdict handed down to Marcos "rejects" the clan's attempt to revise the history of the Martial Law years, which was marred by killings, torture, disappearances, media oppression, and corruption that has left the Philippine economy reeling to this day. He has also allowed the late dictator's body to be buried in the country's heroes' cemetery in 2016.