Delucchi, who had the option of reducing Peterson's sentence to life in prison, called the crime "cruel, uncaring, heartless and callous," the Associated Press reports.
Following the jurist's declaration, relatives of Laci addressed Scott in court, and, in emotionally charged statements, asked him to contemplate what he did to Laci and members of her family.
Laci's sister, Amy Rocha, called Scott "a monster" for "murdering my sister." At one point, Scott's father Lee Peterson was escorted out of the courtroom after yelling, "You're a liar!" while Laci's brother, Brent Rocha, was on the stand.
More on Scott Peterson
Peterson, 32, was convicted Nov. 12 of two counts of murder in the deaths of his wife and son, Conner. The jury recommended the death penalty a month later.
Peterson, who never testified at his own trial, did not address the court. A private escort was expected to take Scott to San Quentin State Prison within the next 48 hours.
San Quentin is located on San Francisco Bay – the same body of water in which the remains of Laci and Conner were found months after their murders. Because of the severe nature of the case, which involves the murder of an unborn child, Peterson is likely to be a marked man in prison. San Quentin officials have admitted as much to news outlets, saying that it will be difficult for them to prevent Peterson from being harmed by other inmates.