Acting under the newly ratified Corrupting of Political Life Law, which bans certain figures who served the ex-president, the Supreme Presidential Electoral Commission made Shafiq the latest person to be expelled from next month's vote, Egypt's Ahram reported.
Three other leading candidates were banned from the race earlier this month: Salafist Hazem Abu Ismail, because his mother had an American passport; the Muslim Brotherhood's Khairat Al-Shater, due to a recent prison sentence, and Mubarak intelligence chief and vice presdent Omar Suleiman.
Shafiq was a longtime minister under Mubarak, the president who was overthrown following mass protests in January and February of 2011. He was also the last prime minister appointed by Mubarak, and served for a total of 33 days before the military took control of the country.
The decision to bar Shafiq could actually be a blow to the ruling Supreme Council of the Armed forces, which many in Egypt think is using the presidential elections to hold onto the power it's supposed to be giving up. Shafiq, who was once the commander of the Egyptian Air Force, was the last remaining candidate with a military background, and many saw him as the SCAF's top choice.
Shafiq's campaign said on Tuesday that it will appeal his ban in court, Ahram reported.
The current frontrunner is now Amr Moussa. Although he served as foreign minister under Mubarak, he hasn't yet been disqualified from running. Moussa is also the former secretary-general of the Arab League, and has impressive name recognition at home and abroad thanks to years as a diplomat in countries like the United States and Switzerland.