Mr Abhisit and Phra Suthep have been charged with premeditated murders and attempted murders in violation of Sections 80, 83, 84 and 288 of the Criminal Code for ordering the military crackdown on the red-shirt protesters between April 7 and May 19, 2010, which resulted in up to 98 deaths and hundreds of injuries. Both defendants denied the charges.
At the time, Mr Abhisit was prime minister and Phra Suthep deputy prime minister in charge of the Centre for Resolution of the Emergency Situation (CRES).
They appeared in court to go through documents and evidence related to the case.
The prosecution earlier filed two separate lawsuits against them. The Criminal Court, at the defendants' request, agreed to combine the two lawsuits as one.
The court adjourned further proceedings until Aug 28.
Mr Abhisit arrived at the court first. Phra Suthep, wearing a yellow robe, arrived later with Akanat Prompan.
Mr Akanat, the spokesman of the People's Democratic Reform Committee (PDRC), said he met Phra Suthep when he arrived at the airport this morning and took him to his house for breakfast before proceeding to the court. Phra Suthep is now living at a temple in Surat Thani.