Egypt's Prosecutor General Hisham Barakat, 65, has died following the bomb attack on his vehicle, officials said.
Earlier it was reported that he had sustained minor injuries in the attack the bomb targeted his convoy near his house in Misr el-Gedida district in Cairo. But later it emerged that he had succumbed to his wounds in a hospital after undergoing a critical surgery.
At least three other people apart from Barakat were injured in the incident, spokesperson of the Ministry of Health Hossam Abdel Ghafar said.
The security forces cordoned the area and were on the lookout for the attackers.
Barakat has referred thousands of Islamists to trial since the overthrow of President Mohammed Morsi in 2013. He has received death threats in the past.
The Egyptian affiliate of the Islamic State group recently called for attacks on the judiciary, after the hanging of six militants.