Magistrate Ajay Kumar Sharma pronounced the quantum of punishment amid tight security arrangements in the court.
"The court awarded death penalty to four convicts under IPC section 302 (punishment for murder) for planting bombs at different places," Public Prosecutor Sri Chand told reporters.
On Wednesday, the court had convicted Mohammad Saif, Mohammad Sarwar Azmi, Mohammad Salman and Saifurrehman. Another accused, Shahbaz Hussain, was acquitted with the court giving him the benefit of the doubt.
The serial blasts rocked Jaipur on the evening of May 13, 2008 within a two-kilometre radius in the walled city, popular also with tourists.
Shahbaz Hussain, a resident of Lucknow, was accused of sending emails to the police claiming responsibility for the blasts on behalf of the Indian Mujahideen. But the allegation could not be proved and he was acquitted.
Apart from these five, two accused were killed in the Batla House encounter in Delhi in the same year and five others are still absconding.