Roughly half of the ministers in the reshuffled cabinet are new.
The new team was meant to take office on Monday but the ceremony was delayed amid wrangling which led to Prime Minister Essam Sharaf's brief hospitalisation with exhaustion.
Sharaf had hoped the new cabinet would mollify activists who have been camped out in Cairo's Tahrir Square since 8 July, but they have rejected the new line-up, which retains several ministers they want sacked.
According to a list published on MENA, the official news agency, several controversial ministers kept their posts, including two appointed under ousted president Hosni Mubarak.
The protesters wanted Sharaf to replace Justice Minister Abdel Aziz al-Gindi, whom they accused of delaying trials of former regime officials, including Mubarak himself.
Activists have called for a mass demonstration on Friday, dubbing it the "Decisive Friday", while hardline Islamist groups say they are organising a counter-demonstration for "stability."
It will be the second cabinet to take office in the face of protests since a nationwide revolt overthrew Mubarak in February.