The Supreme Presidential Elections Committee reinstated Ahmed Shafiq, who served as civil aviation minister for a decade before becoming prime minister in the final three months of Mubarak's reign, Ahram Online reported.
The 12 other contenders who will be on next month's ballot are independent Islamist candidate Abdel-Moneim Abul-Fotouh, former Arab League chief Amr Moussa, Mohamed Mursi of the Muslim Brotherhood's Freedom and Justice Party, Nasserist candidate Hamdeen Sabahi, socialist candidate Abul-Ezz el-Hariri, Revolutionary Socialist candidate Khaled Ali, Islamist politician Mohamed Selim el-Awa, reformist judge Hisham el-Bastawisi, former intelligence officer Hossam Khairallah, ex-police officer Mohamed Fawzy, Egypt Kanana Party candidate Mahmoud Hossam and former Foreign Ministry official Abdullah el-Ashaal.
Shafiq had appealed an earlier ruling that he was ineligible under a law banning figures associated with the Mubarak regime from participating in politics.
Several other candidates have been excluded, including the Brotherhood's Khairat el-Shater, Salafist preacher Hazem Abu-Ismail, former intelligence chief Omar Suleiman, Ghad al-Thawra Party leader Ayman Nour and lawyer Mortada Mansour.
Egypt's presidential campaign starts Monday with the election taking place May 23-24. If no candidate gains a majority of the votes, a runoff will be held June 1-17. A new president will be named June 21, setting the stage for the country's military to formally hand over its executive powers.