Kenyan cult leader Paul Mackenzie and 29 associates have been charged with the murders of 191 children, whose bodies were discovered among more than double that number buried in a forest.
All of the accused rejected the charges filed before a court in Malindi.
One suspect was deemed mentally unfit to stand trial.
Prosecutors claimed Mackenzie ordered his followers to starve themselves and their children to death so they could get to heaven before the world ended, in one of the biggest cult-related calamities in recent history.
The followers of his Church lived in several secluded settlements in an 800-acre area within the Shakahola forest.
More than 400 bodies were eventually exhumed.
Mackenzie was arrested last April.
He has already been charged with terrorism-related crimes, manslaughter and torture. He was also convicted in December of producing and distributing films without a licence and sentenced to 12 months in jail.
A former taxi driver, Mackenzie forbade cult members from sending their children to school and from going to hospital when they were ill, branding such institutions as Satanic, some of his followers said.
Mackenzie’s lawyer has said he is cooperating with the investigation into the deaths.