David Turpin, 56, and Louise Turpin, 49, are facing charges of torture, abuse and false imprisonment.
They were arrested after their daughter escaped from their home where police found some of her siblings chained to their beds and severely malnourished.
The couple appeared in court hours after prosecutors detailed the horrific abuse allegations against them.
Riverside County District Attorney Mike Hestrin said the couple had allegedly punished their children by tying them up – first using ropes and later chaining them to their beds with padlocks.
He said the alleged punishments would last weeks or months, and intensified over time.
Prosecutors said circumstantial evidence showed the children were not released from their chains to go to the toilet.
The teenager who escaped and alerted police to the house where her siblings were held captive had been hatching a plan to leave for two years, Mr Hestrin added.
He detailed some of the gruesome allegations against the parents at a news conference on Thursday.
This case has sent waves of revulsion across the US and beyond, and the small courtroom was packed as the defendants appeared.
David and Louise Turpin were smartly dressed. They occasionally glanced at each other across a table weighed down by a copy of the California penal code and a sheaf of paper related to the case against them. A lawyer sat between them.
Mr Turpin, with a distinctive mop of grey hair, was chained around the waist, his stomach protruding from beneath the metal links. His wife’s mouth was turned down in a glum expression.
The couple spoke only briefly and softly to confirm that they understood and accepted procedural details relating to their next hearing.
The charges they deny are among the most serious any parent could face: amounting to a grievous betrayal of their own children, a betrayal which prosecutors allege went on for years, if not decades.
The siblings themselves are said to be doing well but at least some of them have almost certainly suffered irreparable damage, both physical and mental from their ordeal. (Courtesy BBC)