Chiluba had briefly appeared in court on Tuesday, but proceedings only started on Wednesday with the cross-examination of a witness.
There were intermittent breaks during the trial to allow Chiluba, who suffers from heart problems, "to refresh himself", Emmanuel Mwamba, the former president's spokesman said.
The trial was suspended in May last year when the former leader fell ill.
It had originally begun in 2003 and has been delayed by legal technicalities and Chiluba's medical condition, which had led him to be flown to South Africa for treatment.
Chiluba has denied any wrongdoing and accuses his successor, Levy Mwanawasa, of a political witch-hunt.
On Tuesday he rejected a proposal by the court and state prosecutors to follow the trial by a video link between his home and the court.
Although many of the charges against him have been subsequently dropped, in May 2007, the UK's high court found Chiluba and his associates guilty of stealing $46m in state funds.
However, Chiluba refused to recognise the authority of the UK court and has warned that the judgment would prejudice the Zambian court against him.
The court said the trial would continue on Thursday.